FabSpeed Porsche 991.2 GT3 / GT3 RS Side Muffler Bypass Pipes (2017+)



Optimized design that replaces the heavy and restrictive factory GT3 side mufflers for improved exhaust flow, increased dynamic sports car sound and huge significant weight savings.                                                                                           

Utilizing super premium Helical U.K. Aerospace grade valves along with the addition of O2 bungs, Fabspeed's Side Muffler Bypass Pipes provide the ultimate street and track solution for the 991.2 GT3 / GT3 RS. Prefect upgrade for any Street Driven GT3 touring, GT3RS, Gt3 PDK cars. Factory Sport Button PSE is 100% retained with Fabspeed GT3 side muffler bypass pipes with exhaust valves. NOTE- only Fabspeed Motorsport USA uses Helical Limited ENGLAND exhaust valves on all systems. Porsche uses Helical exhaust valves on their GT3 mufflers because the valves are BulletProof silica carbide. FYI- Ferrari, Lamborghini, McLaren, Aston Martin all demand and use Helical Exhaust Valves UK. for their sports cars and hypercars because only Helical doesnt melt, crack, break, flutter or rattle. 


We chose to use Helical Valves on our 991.2 GT3 / GT3 RS track exhaust systems for their unprecedented quality - which have been proven by many OEM manufacturers such as McLaren, Ferrari, Lamborghini, and many more. Helical valves are an integral part of our Side Muffler Bypass pipes, opening and closing with precision to control the gas flow and optimizing engine back-pressure for improved performance. Helical’s extensive experience in high-volume OEM automotive applications has led to standard features such as an extremely durable pneumatic actuator, precision flat sealing faces inside the valve, stiffening ribs and Ultra high temperature high-temperature bearings at both ends of the butterfly spindle. Helical is an Aerospace Company that also makes exhaust components. Fabspeed Motorsport USA is the USAs exclusive importer buyer. 


We relocated the O2 bungs from the collector of the headers to the Side Muffler Bypass Pipes in order to maintain factory-like functionality with our Long Tube Competition Race Headers - allowing them to read all cylinders while maximizing the performance of the collector. This design will replace our existing SMBP’s allowing you to upgrade to our Long Tube Race Header design at any time in the future.  Extra oxygen sensor ports also allow Data Acquisition at any time. Another value added feature only from Fabspeed.                                              


  • Fits all Porsche 991.2 GT3 / GT3 RS vehicles worldwide
  • Highest quality OEM Porsche Ag. Helical Limited United Kingdon exhaust valves are used. Same exact part number as Porsche Germany chose. Very very expensive but Bullet-Proof reliability. 
  • Includes O2 bungs and plugs at no extra charge.
  • Saves 41 lbs 18.6 kg from the rear of the vehicle
  • CAT-BACK Emissions legal. Bolts onto OEM Porsche catalytic converters!
  • Replicates aggressive CUP car sound for the street. 100% acceptable for a Daily Driver too.
  • 14-16ga T304 Stainless Steel construction
  • retains Sport Button PSE functionality. 
  • Simple bolt-on installation- remove rear left and Right side mufflers and install these Works of Art. 
  • Caveat Emptor-  any cheap valves that is not Helical will 100% fail and leave you stranded or rattling driving one insane. If its not Helical and engraved on top Helical UK Ltd- you have made a grave mistake. 
  • 25+ years of Performance Passion and Perfection. 
  • All Fabspeed performance products are backed by the Fabspeed Lifetime Warranty

Click Here For Install Instructions for Porsche Homelink Connection For Valvetronic Exhaust Control