RoadsterSport SuperStreet for MX5-ND
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RoadsterSport SuperStreet


Stainless Steel PREMIUM ADJUSTABLE MX5 Miata Exhaust

Helmholtz Chamber Design Means Max Fun.

Just 14 pounds!

Gains 8hp in independent magazine tests!
ETA for next batch is mid January

PART NUMBER: 61-1787


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Reg. Price: $688.85

Sale Price: $599.00

Prepay For Next Delivery



Free shipping offers apply only to destinations within US Lower 48.

Reg. Price: $688.85

Sale Price: $599.00

Prepay For Next Delivery



Free shipping offers apply only to destinations within US Lower 48.


WHY: Because YOU want to have fun!
HOW: Helmholtz Technology in a Miata Muffler for the First Time!
WHAT: A 2016+ Miata Muffler that you can control, aggressive throaty burble fun when you want with wide open throttle, and super mild when you want to just cruise.

This is a modified version of our all helmholtz Race muffler that adds an ultra efficient high density resonator before the tip to lower the volume while keeping the fun burble and playful character of our Race muffler. We also dress it up with a unique ultra light version of our 3.5 inch RoadsterSport rolled tip pictured below to finish the look for our street customers wanting something more luxuriously finished than the aggressively lightweight Race muffler:

Result is a 14 pound wonder of a street muffler, you get the great look of the RoadsterSport 3.5 rolled tip, the clean flow of 2.5 inches of pipe from start to finish with smooth mandrel bends on the shortest possible path from the midpipe to the exhaust cutout to max your horsepower gains...and minimal weight with these features. How much POWER? Grassroots MotorSports Magazine backed up our dyno results in the December 2016 issue, they tested and found peak gains of 8hp with no other mods, excerpt of that article below:

CLICK HERE to see the full article covering our SuperStreet muffler.

This muffler gives your right foot lots of control over the volume. The effect of the Helmholtz is very frequency specific such that under decel it can get mild and quiet, yet when you push hard toward redline it sounds exotic and racy. With the top down lots of fun throaty burble, but dramatically more tame when the top is up. In brief, FUN when you want it, and mild when just cruising.

How did we do it? We outfitted our 2016 with a computer and sound analyzer and microphones and drove it under varying conditions and loads with and without muffler. We then use that data and some special software to calculate the particulars of the Helmholtz chamber to precisely knock down the frequencies we do not want to hear in the car while allowing the good throaty burble fun sounds to pass through. All this in a muffler that is just 14 pounds, a nice savings over the 21 pound factory muffler.

Ride Along with our RoadsterSport Super Street in a Launch Edition owned by local customer Mark Booth below, big thanks to Mark for the great video!

SHIPPING NOTE...ships factory direct to you. All POLISHED stainless steel construction. Uses stock hangers and connects to either our RoadsterSport midpipe or the stock midpipe.

Proudly made in the USA, emissions legal in CA and every other State of the Union.

The SOUND level is Adjustable by YOU, INCLUDES removable cone baffle insert in the tip that helps YOU select final sound level, baffle in for reduced sound level, and baffle out for more sound...and just one bolt under the tip to make the easy change. Sold separate is an optional packed baffle that cuts the sound a little more if you want...but most won't!

Proudly made in the USA...with a LIFETIME WARRANY!

BRIAN'S APPLICATION NOTES: Famous Miata Racer Andy Hollis recently did his own dyno tests of this muffler and found it flowed as well as no muffler at all, with solid HP gains over the stock muffler, and he added: "BTW LOVE the sound!" Andy's dyno sheet reprinted on page 24 of our forum ND development thread and bottom of this page. Our Race and SuperStreet Twin Tip share the same straight pipe design with result they will make the same horsepower gains, but this is the customer top choice on sound when used without baffles. The little resonator just slightly civilizes the rowdy RoadsterSport Race, it's still very aggressive, with just a bit less high frequency notes in the balance than the pure Race.

Mild when cruising on otherwise stock ND, delivering a classic sports car BARK and THROATY RUMBLE when you wind it out to redline, lots of fun burble when just playing with the throttle around town. Result is TONS of fun, will make many of you laugh out loud. You also get the best performance from the straightest and cleanest flow out the exhaust cutout you can get, and much lower weight. Nonetheless, this choice is NOT for the faint of heart!!! The most common question we will get on this one is: "will it be too loud" and we cannot answer that one for you because the "right" sound level is a matter of entirely subjective personal preference. Our experience is that owners of Automatic transmissions prefer any of our SuperQ choices. This is an aggressive sounding muffler for those who like to go for the redline often!

Not designed for use on car with aftermarket header or aftermarket midpipe, designed for max fun on otherwise stock exhaust system. Adding header adds a massive amount of sound, thus we suggest customers considering adding a header should look to our SuperQ choices for best control of results with header change. The issue with using adjustable length midpipe with this ultra light three hanger design is that customers rarely get the adjustable length set correct and that can put too much stress on the connection between helmholtz chamber and straight pipe. So if you insist on adding midpipe with this design be careful to get length of midpipe accurate (hangers aligned nicely straight up and down for midpipe) and use thicker hanger from the rear to better support the bigger midpipe.


Installation of this Miata exhaust is SUPER EASY...just two 14mm bolts to loosen! When you open the big box you will find separate foam wrap on the exhaust tip, leave that foam around the tip during your install to protect the polished tips and your car's soft plastic in the exhaust cutout. Use gloves. Note the 'bolts' from the factory are actually studs with springs and nuts and the factory usually jams the nuts on so hard that unbolting it will bring the stud out too. If that does not happen then use 13mm long socket to unscrew the studs (or use jam nut technique where both nuts are put on one stud against each other and then wrench used on the inner of the two to back out the stud). Then lube up the stock exhaust hangers with dish soap and yank stock muffler back and forth to work the soap into the rubber hangers and then the muffler will slide off those rubber hangers easily. Then hang the new muffler on the wet and soapy rubber hangers and torque 'bolts' with the springs back in place to 30ft/lbs. Now you can remove foam tip wrap. Option to remove the baffle too, to do so loosen bolt that holds it from under the exhaust tip and use it as handle to shake the baffle loose and then unscrew bolt the rest of the way and pull the baffle (pulling baffle raises the sound slightly). IF not removing baffle, check torque, 15 ft/lbs on the retaining nut will be enough thanks to lock washer included. Note the muffler to midpipe joint is a ball socket connection for the first time on a Miata, it is designed to move a lot, so please do not add sealants that will gum up that dry ball socket joint. Our pipe size is bigger than OEM for best performance/flow, that means the stock donut gasket sinks a bit deeper than with factory muffler 'mouth'. Our flange is designed as a dual purpose item that allows going to flat gasket if you later go with our 2.5 inch midpipe, at which point the midpipe has a flex joint to replace function of the donut and you get a clean 2.5 inches of flow all the way, which is not possible if we stay same small pipe of stock muffler. After install hold you hands about 2 inches from gasket connection with car running to check if you feel 'puff puff puff' indication of leak against your hands, if you do check your install or replace the factory gasket (our item 61-2144, factory part number RFK2-40-581 )



Super Street leaving the line at SCCA Autocross event.

Easily UNDER our local SCCA sound limits on otherwise stock Miata (our SCCA limit here is 93 db at 50 feet and even in the rain our testing found it easily under our strictly enforced sound limits). Also easily under the most strict 92db days at Mazda Raceway Laguna Seca when used on otherwise stock ND.

Dyno Results! From Grassroots MotorSports Magazine's testing, 8 hp from just a muffler on ND1...when the muffler is a straight pipe design like RoadsterSport Race and SuperStreet Single Tip and SuperStreet Twin Tip.


Stubby Antenna
Stubby Antenna

MIATA MX5-ND 2016-2022

On Sale
Progress Technologies ND MX5 Miata FRONT and REAR AntiSway Bar Combo!
Progress Technologies ND MX5 Miata FRONT and REAR AntiSway Bar Combo!

MIATA MX5-ND 2016-2022

Our BEST All Purpose Sways, Street, Autocross, Track!



On Sale
Packed Baffle Insert for RoadsterSport SINGLE TIPS.
Packed Baffle Insert for RoadsterSport SINGLE TIPS.

MIATA MX5-ND 2016-2022

ETA for next batch is mid March



On Sale
Progress Technologies MX5 FRONT Sway Bar





Customer Reviews

RoadsterSport SuperStreet

Well I must say that I love the sound of the GWR RoadsterSport Super Street! I am overly critical of most things in life and tend to have buyers remorse. Not with this purchase.
I took about 20 minutes to install and went straight out for a drive with the baffle in. It was love at first sound. I drove it for a day and then tried it without the baffle. It, imho, sounds much better without it. It puts a smile on my face every time I start the engine and take it out for a drive. My wife loves it too.
One (negative) point, there was a few imperfections on the finish. Like small metal particles on the stainless steel. No biggy but something to note.
Overall great exhaust and really great sound. I would recommend this without hesitation.

Matthew roberts

Came from GWR Super Q & SSST is a much louder exhaust by comparison. But that SOUND from SSST is just glorious! I also ordered packed baffle for long distance driving.

Lining up your trunk with a layer of 80 mil sound deadening pad helps a lot with booming noise.

I hate to say I disliked anything about my Miata but the OEM exaust was just not doing it for me.. Like everything else I researched the heck out of exausts for miatas and decided to settle on this. Boy am I glad I did! It transformed the car completely!! I love the growl it has now and its still very livable. Even my wife loves the way it sounds! Also I liked to note that i seriously think it gives the car more Horse Power. I immediately noticed a more aggressice throttle response and torque. Best $500 I every spent Thanks Good Win!!

What a quick and terrific upgrade to an already great car. As many others have said, this is the proper tone and volume of exhaust that this car should come with. For me it's the perfect amount of subtle rumble on a cold start, no drone when driving, but then when you put your foot into it you get the bark, the volume, the pop pops and all the things that we all bought MX5s for in the first place! Install was a little stubborn on the stock bolts, but a good impact wrench zipped those right off and then the rest of the install was very easy and straightforward. I thought I would have needed ramps to get under there properly, but did it all in my driveway without ramps and knocked it out in 10 minutes. Great product, quick shipping and really great craftsmanship!

Received the muffler after a bit of a wait but it was worth it. It took me maybe 30 minutes to remove the old muffler and install this one so I would say that this is probably the easiest DIY upgrade outside of replacing the antenna. There are plenty of muffler sound videos on YouTube but none do this one justice. I cranked up the car and the smile was instant. My sportscar sounds like a sportscar now and not a hybrid. The muffler has a nice tone at idle but not obnoxious. Acceleration is when it shows its true colors. Loud and clear with no raspiness when you let off the pedal. No drone on the highway. This muffler should be on everyone's wish list.

I was kind of stressing out over which exhaust to choose as this is my first time modifying a car. I was gonna go with the FM exhaust but I thought the install was gonna a little too much for a first timer. I was also concerned about having a vacuum leak. I then decided to go with an exhaust from Good Win Racing. With all the options I had no idea which one to go with. I decided the SuperQ was gonna be too quiet and the race was gonna be too loud. I went with a middle of the road approach and could not be happier. This exhaust can actually be controlled with throttle input. When your not on it, you can kind of tell it's there. When you are on it however, It is amazing. It's loud enough but not too loud. What surprised me most was at highway speed you barely notice it. This is exactly what I wanted. This exhaust is also well priced and as a first timer, a very simple and easy install, only took me 30min.

Have now had this on the car a little under a week. The furnished insert was pulled out from the start. The volume levels are perfect with the top up or down. Do not be concerned about it being too loud... it's not at all, plus if for some reason you need to tone it down, the options are there to do that.

Great sounding system and the car feels stronger and revs faster too. Maybe it's in my head but I don't think so. Here's something interesting: It seems that the MPG have dropped by 1 or 2 mpg. Maybe because exhaust gases are being scavenged out at a higher rate? Or... I'm having way too much fun. I also find it easier to hear my shift points too as the stock system was too quiet.

Overall this is an awesome design and you can't go wrong. Great job Good-Win!!

Hi Ken,
Glad to hear you're loving your muffler! Regarding your note about MPG, nothing about the muffler reduces efficiency - in fact, it improves it, if anything. However, we do hear from lots of folks that after installing a great sounding muffler they tend to push that right pedal down a little further, run the RPMs a little higher, etc. because they're having so much FUN... and that change in driving style can of course mean a slight reduction in MPG.
-- The Good-Win Racing Team

I recently bought this guy. I'm too old, decrepit and just too damn lazy to do the install myself. Lucky for me I have a local shop was willing to do the swap with the factory unit.

OHMYGAWD!! What a difference! I took the IMHO useless insert out of the tail-end and sought to see if it would be too loud or not... NOT AN ISSUE!! Great sound. I "think" I could feel some acceleration gains but it just might be excitement over the whole experience. Durn... I like this a LOT!

Good job Good Win folks. I'm very, very impressed.

Excellent tone with a higher-pitched sound at the upper rev range and a rumble at lower and lower-mid range. No noticeable drone. Good-looking, OEM-type fitment with an easy-to-keep-clean chrome finish. Never needed the baffle because the volume is just right for all uses and is easily modulated with throttle inputs.

This is the PERFECT street exhaust for someone who enjoys hearing their car's exhaust, but doesn't want it constantly droning in their ear and drowning out any conversation in the car. For reference I installed it with the roadster sport midpipe so its even a little louder than with the factory midpipe. That being said, when you're cruising top and windows up, this thing is nearly silent, just a faint little growl that you can very easily talk over. I've heard factory exhausts drone more cruising than this does. When you lay into the throttle its definitely there but again not ear piercing loud. Just the right amount of sound to sound great and not be obnoxious. Never drones at all at any rpm, and has a nice low pitch tone to it with no rasp or ricey tones. I love this exhaust!

Had the stock exhaust on my 2018 Club for almost 3 years before deciding I needed a bit more sound. I have to say that this exhaust from Goodwin is exactly what I was looking for. Really opens up the sound of the 2.0L without sounding over the top. I was initially worried it would make the car sound more on the "ricer" side, but the deep tone and overall sound at any RPM is awesome both inside and outside the car. I had my friend do a couple of drive-by's after installation (which took about 20 minutes) and the tone of this exhaust is unique and perfectly suited to the car. The additional sound gives the car so much more personality. The installation was also very straightforward. However, I recommend to get a new donut gasket (either from your local dealership or from Good-Win) to make sure the seal on the dry joint is perfect. The construction and look of the exhaust was extremely high quality and the packaging during shipment was impressive. Anyone on the fence between this and any other exhaust on the market look no further; I spent hours on research and reviews and finally settling on Good-Win left me with no regrets!

The MX-5 is a blast to drive in the North Carolina mountains, but if there is something lacking it is the exhaust sound... It just doesn't make the car sound like a sports car! Problem solved... With the Goodwin Racing Roadster Sport Super Street. The feedback is night and day and when you open up the throttle or downshift heel-toe and give it that pop of revs, you can't but have a big smile on your face :) I did hope for a little more burble and pops... Not that there aren't any, I just thought it would be a little more noticeable, but that may develop more over time.

The Goodwin Racing exhaust is gorgeous to look at... Fine workmanship and beautifully polished SS. Once installed, it also looks great and the tip is not obnoxiously large. It looks a lot like the classic exhausts you would expect to find on a vintage sports car.

Installation was a breeze! For removing the factory exhaust, I PB Blasted the nut welded to the flange and gave a slight tap on the wrench to break the bolts' bonds. They both came off the flange pretty easily. For the hangers, I just invested in a hanger removal tool and used a bit of WD-40 to lubricate and they slipped right off. The OEM exhaust is surprisingly heavy, so from a weight standpoint, the Goodwin Racing option has the added benefit of being much lighter. Fit was perfect and hanging the new exhaust took less than a minute. Tighten the bolts that keyed in perfectly and your all set! First cold startup and the grin tells the story :D

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