SKU: 38561465406

Fabspeed 981 Cayman GT4/Spyder Valvetronic GT3 Muffler Conversion Kit (FS.POR.981GT4.GT3CKBR)

$1246.02 $1384.47
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  • USA
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Ships within 48 hours · Estimated delivery Sep 13 - Sep 18

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Description

Fabspeed 981 Cayman GT4/Spyder Valvetronic GT3 Muffler Conversion Kit (FS.POR.981GT4.GT3CKBR)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: 38561465406

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4.9 ★★★★★
Based on 15 reviews
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R
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robert ferrell
Lexington, US
★★★★★ 5
Good
Color: Black, Size: 6 Panel
Love it , just what so needed , easy to put together (some what ) …
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 16, 2026
C
Verified Purchase
Crimm
Whiting, US
★★★★★ 3
Decent for the price. Instructions suck but most people should be able to figure it out. More below.
Color: Black, Size: 6 Panel, Color: Black, Size: 6 Panel
SUMMARY: 3 stars from me because it's firmly average. It's fine for the price. Assembly and materials are alright but I can see some caveats depending on your circumstances. Assembly instructions do a subpar job of pointing out some details. ASSEMBLY INSTRUCTIONS: Maybe it's because I'm autistic and/or building model kits and assembling stuff is my jam, but I honestly thought people were exaggerating when they were complaining about the instructions and I'd be able to flex my ~superior assembly skills.~ I was wrong! These instructions genuinely suck, and whoever is responsible for making them should be ashamed. The instructions do a poor job of calling out some details regarding orientation of parts, and some of the images do not actually match the physical parts. For example, it does not really outline the assembly of the end panels clearly, and I can see someone accidentally using the wrong poles. I've drawn over a photo to show what you should do to try and make it clearer. Additionally, the manual shows a flathead screw for bolting the feet into position, but the actual screw is not a flathead. It also does not point out the counterbore, so if you aren't paying attention you may put the foot pads onto the wrong side of the foot. It's also missing the fact that you need to use another one of the plastic pieces when you finish assembling a panel. ACTUAL ASSEMBLY & MATERIALS: To their credit, all of my bags were clearly labeled. The assembly process wasn't difficult. It's mostly just tedious and requires a fair amount of space. I was able to assemble it by myself without any real difficulty. However, the way it's assembled means two things. One, the fabric parts aren't removable without disassembly. So if you want to use this in an environment where they would require cleaning, I would seriously recommend looking for another option. Or, you could buy this just to use the frame pieces and then somehow buy or make your own fabric pieces designed to be removable with velcro or something. Two, because of the materials I really don't have a lot of faith in this thing surviving disassembly and reassembly. Like a lot of sorta-cheap-but-convenient furniture, it uses those spring-button connections and plastic inserts with self-tapping screws. Those things are not really meant to be disassembled and rethreaded. It also relies a lot on the tension of the poles and the fabric to keep everything rigid and squared, which I think puts a lot of pressure on the aforementioned buttons, plastic inserts, and the hollow metal rods. So I feel like that will also cause issues with disassembly and reassembly. Basically once this thing is assembled, it's not really meant to be disassembled. The best you can do is spot-clean the fabric if you need to. Speaking of the fabric, I didn't see any labels on them or anything in the manual that says what they are, but they feel like some kind of polyester. They generate static electricity pretty easily, and pet hair and debris sticks easily. So that's another downside of them not being easily removable. For the most part it does seem pretty stable. The poles seem to be pretty uniform in length so they're all making contact with my floor. Obviously this isn't structural so it shouldn't be supporting anything, but the two main feet seem to be doing fine with keeping this thing upright. CLOSING THOUGHTS: Really, it's fine for what it is, but it could be better in a lot of little ways and the substandard quality of the instructions just seems unprofessional to me, which is why I'm being so harsh with my rating. Depending on your needs and environment you may want to consider a different option. Preferably one that is made to be disassembled with better materials, and/or one with fabric pieces made to be removed easily.
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Reviewed in the United States on May 28, 2023
B
Verified Purchase
Barb
Phoenix, US
★★★★★ 1
Not as it seems
Color: Black, Size: 6 Panel
these are awful... Each individual panel is fine, but when you put it together it can barely stand up, and the clips that hold it together keep popping off. Steer clear of this item.
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Reviewed in the United States on April 7, 2026
T
Verified Purchase
Timothy Beckner
Boise, US
★★★★★ 5
As described
Color: White, Size: 6 Panel
Works great in my clinic
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Reviewed in the United States on May 17, 2026
C
Verified Purchase
Chara Reed
Boise, US
★★★★★ 5
Perfect add to bathroom
Size: 24x6 2Pcs, Color: White
These are perfect. They are just as advertised. They are easy to hang and all needed materials come included (screws and different drywall hanging options).
WAS THIS REVIEW HELPFUL?YesReportShare
Reviewed in the United States on May 18, 2026

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