SKU: 3149987790

Fabspeed 981 Cayman GT4/Spyder Valvetronic GT3 Muffler Conversion Kit (FS.POR.981GT4.GT3CKC)

Sale price$1246.02 Regular price$1384.47
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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.GT3CKC)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: 3149987790

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4.2 ★★★★★
Based on 15 reviews
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T. Hoffmann
West Palm Beach, US
★★★★★ 5
Great for tall, slender teenager!
Size: Small, Color: Light Grey, Size: Small, Color: Light Grey
Finding a suit for a tall, slender teenage boy is about as hard as climbing Mt. Everest. Until I found this one!! I was so pleasantly surprised that this suit fit my 15 year old son like a glove. He is 5'10'' and 140 lbs so he needs pants with the proper length and smaller waist. While the waist was slightly big, he didn't need a belt and the pants fell perfectly with a pair of Nike tennis shoes. I ordered a size small and would say the pants were a 32x32 but waist was probably more like a 31. Jacket and vest were a great fit as well. High quality and easy to steam to get the shipping wrinkles out.
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 25, 2026
I
Verified Purchase
IrishPuterGeek
Birmingham, US
★★★★★ 4
Fantastic suite for the price!
Size: Large, Color: Khaki
I purchased the gray version to evaluate the suit. I ordered a size up based on other reviews and was pleased to discover everything fit well. The jacket fit well around the arms, chest, shoulders, and even my seemingly ever-growing gut. The vest was the same. The pants also fit well around the waist (thanks to the expanding waistband) butt, and thighs. The only problem was the pants were about 2 sizes too long. Considering the price point, I was felt I was still way ahead after paying to have them altered. After a couple week's worth of wear, I purchased 4 more (gray, black, blue and tan). All fit the same way and were easily altered too. The tailor even had the cashier ask me where I purchased these as he was impressed with the quality. A couple months in and I'm still pleased, although I've had a few issues. My right pocket on my blue pair has ripped it's seam twice, as has the same pocket on one of my gray pair. Considering it's the same pocket, I would suspect I am just heavy handed but this is not a common problem with any of my other clothes. The pants are a bit on the tighter side when I am sitting down so perhaps the stitching is just not strong enough. I have asked the tailor to give me a super stitch in this area and am just about to pick up the gray pair with this new stitch. I'll try to remember to update later on. Overall, I feel I have really gotten my money's worth out of these suits, especially considering the prices of others. I have been wearing these daily since June and have gotten many compliments.
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Reviewed in the United States on December 3, 2024
C
Verified Purchase
CC Moon
Draper, US
★★★★★ 5
Happy teen for prom. 6'1" 170 lbs medium perfect fit
Size: Medium, Color: Black, Size: Medium, Color: Black
This ended up being a great purchase. My son chose this suit for prom. He made sure to check the reviews and size chart and was very happy with the fit, quality and overall look. He's 6'1", 170 lbs and got a medium. It was perfect.
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Reviewed in the United States on May 10, 2026
D
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didibling
Waukegan, US
★★★★★ 5
Great suit at a great value
Size: Large, Color: Black
I have ordered several other suits from the seller for my three boys over the last several years for either their prom, special events and graduations. The fit and value are wonderful. I would definitely recommend this suit if you want something that is classy looking, but won’t break the bank
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Reviewed in the United States on April 8, 2026
A
Verified Purchase
Amanda Sammon
Waukegan, US
★★★★★ 5
Great Suit
Size: Small, Color: Light Grey
Was a little tight in the shoulders but otherwise fit great and looks good.
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Reviewed in the United States on April 30, 2026

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