RoadsterSport SuperStreet for MX5-ND
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RoadsterSport SuperStreet


Stainless Steel PREMIUM ADJUSTABLE MX5 Miata Exhaust

Helmholtz Chamber Design Means Max Fun.

Under 14 pounds!

Gains 8hp in independent magazine tests!

PART NUMBER: 61-1787


Price: $479.00



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

Price: $479.00



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 13.9 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 under 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 removeable 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 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 2016-2020

On Sale
Progress Technologies 63.1134 ND MX5 Miata FRONT and REAR AntiSway Bar Combo
Progress Technologies 63.1134 ND MX5 Miata FRONT and REAR AntiSway Bar Combo

MIATA MX5-ND 2016-2020

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



Packed Baffle Insert for RoadsterSport SINGLE TIPS.


Progress Technologies MX5 FRONT Sway Bar




Customer Reviews

RoadsterSport SuperStreet

Just hung this on my new to me Miata ND and I have never gotten more "bang for the buck" out of a bolt on car or bike accessory than this.
Install was a breeze, it took me longer to unbox and get the minimal tools needed than it did to do the actual work.
Used my air ratchet and pulled nut and stud out as a unit which gave me the side to side motion needed work the soaped up mounts off the car hangers. Reinstalled the 3 needed hangers on the new exhaust hung it tightened to specs and fired it up.
The initial startup was pleasing but the real thrill is when you take it out, wind it up, or hit a downshift. A wonderful bassy rumble that is not obnoxious but rather complimentary to the already great sound of the Miatas power plant.
Removing the baffle only increases the rumble slightly and I plan on leaving it out.
The single chrome tip looks good as well.
Shipping was fast!!!
My first purchase from Good-Win Racing but most assuredly not my last as I've already ordered a new shift knob and eyeing suspension packages.

Well, my first purchase from Good-win Racing has exceeded my expectations, and I'm very pleased! This care has high-serviceability to begin with, and it looks like Good-win has taken advantage of that. The part quality is top shelf (materials, weld quality and fitment vs OE), and the install was a breeze; I did it in literally 15 minutes and without jacking the car (including trying to find my spray bottle). The hangers came of more easily than I had been led to believe, and I had no issues that evidently some others have had with the studs. The idle is nice and unobtrusive and from there, the note increases uniformly under increased load and is really much more in context with the rest of the vehicle than the stock part. I'll be taking it on the highway tomorrow and will see what happens with the baffle removed. I also have an Abarth 500, and for reference, this is quieter and less aggressive - at least with the baffle in place. If I have anything meaningful to add later on, I will.

Perfect! I was worried the car would sound obnoxious and like it was trying too hard to get attention. Definitely not the case! The sound is a bit throaty with a deep grumble and when the engine starts hitting 7k RPM it sounds mean. And this is coming from a guy who owns some big american muscle cars. I think there is a slight performance increase with it too, could just be the mind dyno but definitely feels like a bit more power. If you are worried about this muffler sounding like an overgrown lawnmower you need not to; this gives the Miata the perfect sound.

I'm no mechanic, but I was able to install this without much trouble. Use dish soap and water mixture on the rubber grommets where the supports for the old muffler go. It takes a bit of wiggling to get it out. Then the new one goes in the same way (with one less). Bolts came off and went back on easily.
I love the sound! I've run with the baffle in and with it out. The baffles does make it a little quieter. I like the sound with and without - generally run with the baffle for daily driving, and take it out for autocross and track days. Totally worth the $.

Fantastic sound, installed in 30 mins. Soap trick was a life saver. With the stock baffle the sound has a much deeper tone in the low range but keeps the stock volume and sound in the higher rpms. Baffle out increases the volume and changes the tone noticeably throughout the rev range, but even baffle out the volume is not obnoxious. 10/10 would recommend.

The MX-5 is an easy car to fall in love with, but having come from cars whose stock exhausts had that low, deep growl when pushed, I found myself missing that. Having read the reviews and watched the YouTube videos, I decided to go with the GWR SSST, and I can barely describe the smile on my face from the very first drive. The tone of the exhaust is perfect. A deep satisfying growl on every pull. I found myself hoping I'll hit every red light so that I can start from a stop again. And the burples when letting go of the throttle, ugh, I find myself urging to giggle every time. This exhaust made an already amazing car one that I'm absolutely in love with, and one that I'm now urged to customize further and make it truly personalized, mine. There is highway drone, which isn't that noticable with the top up, but definitely there with the top down. Still, given how easy it is to take the 30 seconds to put the packed baffle on when we know we'll be on the highway for a while or taking a longer drive / weekend away, it's not a concern.

Beautiful piece of equipment that also saves weight. The single exhaust tip looks great and the sound is slightly more decibels than stock but the tone is much better.

I recently had the RoadsterSport SuperStreet exhaust installed on my 2016 MX-5 Club. Previous to the installation, I removed the sound tube from the vehicle so I could get a good baseline of what the new exhaust added to the motoring experience.
Without the sound tube, the engine note was barely perceptible.
Gadzooks! With the SuperStreet - the car blossomed into a complete fun machine. Now the "go fast" pedal produces an auditory effect that immediately clues you into the attitude of the car. Cruising? - nice and relaxed sound. Hot-shoeing? You know it baby! And that is with the baffle still installed. The upgrade to the motoring experience is tremendous. Not only do I hear it, but I can feel the exhaust vibrations in the chassis as I blast about. I also perceived a little bit of a kick in the pants in the higher rev range that I did not perceive before. It is a very rewarding and exhilarating upgrade.
Well worth the cost and I look forward to many fun miles ahead.
Oh - and the craftmanship and quality of the muffler are second to none.
Once again, Good-win has provided a cost-effective and rewarding upgrade to my vehicle.

This was the first modification I made to our MX5. I read all of the other reviews and watched all the youtube videos prior to buying.

All I can say is this exhaust sounds incredible. Just the right tone, and growl. It makes driving the car even more fun than stock.

Installation was a breeze and I didn't even have to lift the car. Did it right in my driveway. The finish quality was extremely high and the polished metal looks beautiful. Definitely recommend this exhaust for sure.

This is the first mod I did on my 2017 RF. I actually got the exhaust in a week before I was able to track down the Club model I wanted. With less than 200 miles on the car I had the exhaust and mid pipe installed. WOW!! Like...really..the amount of fun this exhaust adds is amazing. A nice throaty burble at start up..never intrusive, and a complete joy to listen to with the top down. For me, this exhaust has been the perfect addition. Not too loud...but loud enough to paste a smile on your face when you're rowing through that sublime gearbox. I cannot recommend this exhaust highly enough!! Just do won't regret it. Oh..and I just put 10,000 miles on my RF which is my daily driver..and the exhaust just gets better and better!

Close to the perfect balance of noise level and tone for a street car. The removable baffle makes it slightly quieter and is nice to have. Easily removes with one bolt. This exhaust doesn't make any bad sounds at any rpm at any throttle %. The tip looks great as well.

I love this muffler. It's used strictly on the street and gives me the not too loud and not too quiet deep sound that I like. Easy install in my driveway was a bonus. At age 62 I sometimes think that I should have grown up by now but I still like a "just right" exhaust note.

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