Porsche 991 GT3 / GT3 RS / 911R SOUL Valved Side Muffler Bypass Pipes


Shed 35 pounds and reduce heat soak while encouraging an exciting exhaust note from your GT3 while retaining valve functionality

+  Fits all Porsche 991.1 / 991.2  GT3 / GT3 RS models including 911R (2014-2019)
+  Weighs 35.4 lbs / 16 kg less than factory exhaust components (44.9 lbs vs 9.5 lbs)
+  Designed and built in-house at SOUL’s Willow Grove, PA facility
+  All Soul Performance Products components are backed by a renowned Lifetime Warranty for both street and track use

SKU: POR.991GT3.SMBV Categories: ,


DEVELOPMENT AND TESTING:  Deleting the side mufflers yields huge weight savings, helps with heat management in the engine bay, and keeps the rear tires cooler. The hole leading into the secondary pipe is enlarged to equalize pressure in the center muffler – promoting longevity. Flex bellows allow for easy installation and increase durability under extreme racing conditions in a similar manner to OEM. Large 3″ diameter primary piping increases flow. High quality valves operate like factory.

SOUND:  The sound is smoother during the transition between open and closed versus a center muffler bypass. Valves closed tone is increased moderately while still comfortable with factory center muffler in place. Valves open reveals a refined, exotic pitch befitting of the high performance GT3 engine.

CONSTRUCTION:  Each set is made from mandrel bent T304L 3″ .065″ wall stainless steel tubing and high quality flex bellows for maximum durability.

BOLT ON AND GO:  Each exhaust is tested in a fixture to ensure perfect fitment and then foam packed to arrive in perfect condition, ready to install with no cutting or modifying required.

LIFETIME WARRANTY:  Enjoy your SOUL exhaust components with confidence on both the street and track as the valves and entire exhaust are covered by our Lifetime Warranty! Our team will quickly work with you to resolve any issues or answer any questions that you may have.

NOTE: O2 bungs can be added (to work with aftermarket headers that relocate the bungs to the SMB). We do not add them by default in the interest of lightness. Contact us for this option.


  1. CobaltCr

    Just installed the valved bypass last night and connected to sharkwerks center. Sound at startup is amazing and the valves open is glorious. Haven’t had a chance to take a drive as it was pretty late when I finished. Will try to get some video but my guess is it will not be able to really capture the sound.

    Install was aided by my quick jack. Lifting the rear let the tires drop enough so I could reach the bumper screws without taking off the rear tires. I would not do this without taking off the rear bumper.

    Under load there is quite a bit of volume and resonance In the cabin. Cruising at highway speeds there is little to no drone. I can’t really tell a difference with the valves open or closed at highway speeds. The volume difference at idle and low rpm is quite noticeably less with valves closed.

    Hope that helps People who are considering a bypass. The soul side bypass is a great piece of kit and my experience has been very positive.

  2. Jack Ippolito

    I purchased the side muffler bypass from Soul PP. Well, all I can say is here is a company that screams performance and product development. They are so juiced up on making your car perform better, sound better, look better and just feel better. I had great experience there, the people there go out of the way to please you. They opened on a Saturday morning so I was able to pick-up my car, they went over pricing, gave me a private tour of the plant and it was a pleasure. John Gaydos who literally knows everything, and I mean everything about exhausts is the person I dealt with, but everyone else there I spoke to was equally knowledgeable and addressed all my concerns. Soul PP gets 5 stars from me! My GT3 sounds incredible and they also surprised me with a brand new set of 4” satin tips that look SICK!

  3. Buteo

    Very livable so far. Quite pleasantly surprised! Ive been staying under 4K rpms for the first 600 or so miles. But just touching. 4K when the valves open it comes alive!

    My tech was quite impressed with the build quality as well. A+ from him

  4. Nick

    Did the install today and went well. Pretty straight forward on the 2019 GT3RS. Definitely sounds meatier and only a slight drop at 1800-2150 RPMs. I’m happy with the decision and think you guys have a great product. I appreciate your attention to detail with packaging as well.

  5. Francis Luu

    I’m a few hundred miles (and a track day) into my Soul valved side muffler bypasses and it’s similar to how others have described it — similar to stock but more. Downshifts and burbles are more pronounced with a touch more bass. Above the RPM threshold that the valves open back up again I’d describe it as a louder bark that retains the factory’s smooth and somewhat high-pitched tone without much rasp at all.

  6. 997TTMeteor

    I had the Sharkwerks center bypass with valves disconnected on my 991.1 GT3 which I thought was great (almost did the same thing here again since this is strictly a road car for me, and I am more concerned about sound than weight/heat) but the side bypass pipes are fantastic, all-round. Amazing tone/richness/depth, quiet enough on low throttle for around town (I definitely don’t need valves for my volume tolerance), and like others have said, it really retains the stock noises, just with a little more/better sound, proper exotic cup-car like tone, just quieter. At some rev levels it barely sounds different than stock inside the car.

    Thanks to John @ SOUL for the great service & advice on this one (always available for a call or email), considering how many options there are now, happy I ended up with the perfect set up for me.

  7. mdrums (Rennlist)

    I was out the other night and I have the Soul side muffler deletes on my .2 GT3. I have unhooked and plugged the valves so it just runs straight through below 4k rpm. Car sound awesome, nice tone below 4k rpm nothing obtrusive, can talk on the phone. tire noise can be louder than exhaust at 70-80mph under 4k rpm. Cruising through a neighborhood not much sound difference than if valves where operating and closed…just a little.

    Keep in mind..I am a drummer…used to loud bombastic things…but the GT3 exhaust in this config is not loud and obnoxious…its really how the car should come and sound from the factory. The fit finish and quality of the Soul side muffler deletes are really really good. I have posted my comments on these before but just wanted to revisit 5 months or so later…still enjoying them and believe in Soul.

    Not sure if I will ever hook the vales back up…its stupid simple if I need to…maybe next year and see what I think.

  8. carbondan (Rennlist)

    I installed my Soul valved SMB 2 weeks ago and have been extremely impressed all around. Best price, perfect quality, excellent packaging, easy install with perfect fitment. Way lower temps, lower weight, nice minor bump in sound with valves closed and incredible sound at full tilt. Can’t recommend this upgrade from Soul highly enough.

  9. Dave’s911 (Rennlist)

    Yesterday afternoon I installed my Soul SMB that I purchased used from forum member SPEEDYJ (great seller BTW). The install was pretty straight forward after watching the videos by Obsessed Garage. The hardest thing for me was getting the bumper cover back in place correctly. Now I ‘ve done it once it’ll be easy next time though. As you can see, I put the car on ramps to make it easier to access.

    Quality of the SMB is great, even used. Drove it a few miles this morning and love the sound. As others have said, its a similar sound to stock, just turned up a little. Definitely a deeper sound idling with the valves open though. Very nice. The car is otherwise stock, for now! Dropped about 36lbs off the backend.

  10. 168glhs1986 (Rennlist)

    The very best exhaust upgrade. Thanks for making these. Dropped 35 ish lbs. Gained some good sound but not too loud. The sound is perfection, especially the downshifts in my 991.2 Touring! Just what the doctor ordered.

Add a review