SKU: 34911357251

Fabspeed 981 Cayman GT4/Spyder Valvetronic GT3 Muffler Conversion Kit (FS.POR.981GT4.GT3CK)

Sale price$1142.07 Regular price$1268.97
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Ships within 48 hours · Estimated delivery Aug 30 - Sep 4

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Description

Fabspeed 981 Cayman GT4/Spyder Valvetronic GT3 Muffler Conversion Kit (FS.POR.981GT4.GT3CK)Porsche Boxster Cayman owners have requested a conversion kit that allows the installation of a Porsche OEM 991 GT3 center muffler onto their cars. Fabspeed Motorsport listened and designed in CAD and built inhouse a lightweight installation kit that allows any 6 speed Porsche 981 GT4 or Spyder owner to install an OEM GT3 center muffler (A PDK version will also be available once we are able to test fitment). This kit also allows the installation of a

Porsche Boxster Cayman owners have requested a conversion kit that allows the installation of a Porsche OEM 991 GT3 center muffler onto their cars. Fabspeed Motorsport listened and designed in CAD and built inhouse a lightweight installation kit that allows any 6 speed Porsche 981 GT4 or Spyder owner to install an OEM GT3 center muffler (A PDK version will also be available once we are able to test fitment). This kit also allows the installation of a Fabspeed 991 GT3 Center Muffler Bypass Pipe or 991 GT3 Center Mini Maxflo Performance Exhaust onto your 981 GT4/Spyder.

The system consists of 2.5" 63.5mm CNC mandrel bent one piece Left and Right side over axle pipes and clamps. Then a set of valved side muffler inlet Y-pipes that retain the factory PSE valved exhaust functionality. The valves are OEM Porsche GT3 HELICAL vacuum-actuated exhaust valves that are imported from the U.K. We use our FLOW Waterjet to cut a CAD designed, lightweight, stainless steel mounting bracket to hold the muffler; hardware for installation is included. This and the Factory Porsche muffler band straps hold everything in place. For tips, you can use the factory 991 GT3 tips or you can order our custom exhaust tip mount with any choice of our signature tips.

SOUND:

Enjoy the characteristic sound of a factory Porsche engineered exhaust but with a nice increase in volume! With PSE off (valves closed), the exhaust is still tame and livable in the cabin. However, with PSE on (valves open) hear that flat 6 howl up to redline! The larger over axle pipes that are included also contribute to the overall louder tone.

POWER:

The 991 GT3 muffler was designed by Porsche to support 475 HP, because of this it flows a lot better than the 981 GT4 muffler that was only designed for 385 HP. We expect this increase in flow, helped by our larger over axle pipes and muffler inlets, to give a nice HP increase. 

FEATURES:

  • Fits all 6 speed manual Porsche 981 Cayman GT4 / 981 Boxster Spyder vehicles (2015-2016). A PDK version will also be available once we are able to test fitment
  • Choose between your choice of Premium Fabspeed Exhaust Tips or use OEM 991 GT3 Tips.
  • CNC Mandrel bent 2.5" 63.5 precision over axle pipes to valvetronic inlet pipes
  • Helical Aerospace United Kingdom exhaust valves- same OEM quality valves used on Porsche GT3, GT3RS. Made with Silica carbide.
  • Constructed from 14-16ga T304L stainless steel tubing for maximum power and durability
  • Direct bolt-on installation; no cutting or welding required
  • All Fabspeed performance products are backed by the Fabspeed Lifetime Warranty

NOTE:

  • OEM GT3 center muffler is NOT included
Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 34911357251

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Benyamin
Lexington, US
★★★★★ 5
Great Shoes by Asics
Size: 9.5 X-Wide, Color: Piedmont Grey/Black
Comfortable and durable as heck; classic Asics quality. I love the casual appearance of it, which means I can wear it on a daily basis too. True to the size.
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Reviewed in the United States on April 11, 2026
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Francismommyof3
Dallas, US
★★★★★ 5
Excellent for a 4E wide foot!
Size: 9 X-Wide, Color: Piedmont Grey/Black
As a female with a wide foot, it is very hard to find a good, comfortable shoe for walking, running and hiking. These were immediately comfortable and really didn't require a break in, although they are more comfortable after a few days of use. My 1st day I put about 5 miles on them and they were great. The cushion isn't like a cloud, but it's there and very responsive. These are very supportive and breathable. I have gone on a few Easy to moderate hikes with them and they're just fine for a dryer trail. They have good grip for rocks as well. 10/10 for these! I will also add that I underpronate, and these provide wonderful stability for that.
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Reviewed in the United States on April 17, 2026
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Amazon Customer
Cuba, US
★★★★★ 4
Great comfort, but not built for long-term daily use
Size: 9.5 X-Wide, Color: Black/White, Size: 9.5 X-Wide, Color: Black/White
I've had this shoe for almost a year now. I use it almost daily on a walking pad while working from home, plus as a gym shoe. After nearly a year of this routine, I've noticed considerable wear on the sole. Don't get me wrong: the shoe is great and very comfortable, looks decent, and fits great at the start, and has good breathability. However, that comfort has started to fade as the shoe has worn down. Gel-Contends 9 is a really good shoe, but definitely not a long-term, heavy-use shoe. Perfect for casual or rotation use, occasional runs, but don't expect it to last 12+ months of daily wear.
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Reviewed in the United States on April 22, 2026
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Giselle
Phoenix, US
★★★★★ 5
Great for the price!
Size: 11, Color: White/Glacier Grey
Bought for husband, he says that they feel comfortable have good cushion & feel stable while he runs. Give him traction on the beach running or on pavement! Sharp looking shoes!
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Reviewed in the United States on May 26, 2026
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Michael Balkovic
Natrona Heights, US
★★★★★ 5
Great shoe
Size: 11 X-Wide, Color: White/Glacier Grey
Probably one of the most comfortable shoes I've ever bought. Great for walking on concrete. Light weight and cool and comfortable
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Reviewed in the United States on May 23, 2026

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