Toggle Nav
My Cart
  • Menu

CMS Ultimate Center Muffler Delete 991.1 & 991.2 Porsche GT3/RS/911R

Competition Motorsport



  • 991.2 GT3 (2018+)
  • 991.1 GT3 (2014-16)
  • 991.1 GT3RS (2016+)
  • 911 R (2016+)

Engineered to deliver even more performance in a slash-cut, dual-outlet design that can't be beat!

Designed and built entirely in the U.S. from the highest-quality four-inch diameter American T304 stainless steel and meticulously TIG welded, the CMS Ultimate GT3 exhaust replaces your heavy, restrictive OEM center muffler.  Engineered to scavenge exhaust pulses to increase exhaust gas velocity and flow, the CMS Ultimate is the only exhaust dyno-proven to add over 14 horsepower and 13 lbs-ft of torque at the wheels while removing 11 lbs. of rear end weight.

On top of increased performance, it unleashes an incredible engine snarl at low to mid revs that turns into an intoxicating all-out flat six wail above 6,000 RPM!  CMS makes driving the 991 GT3 and GT3RS the exhilarating experience it was meant to be. For the more civilized among us, we've engineered out any hint of drone anywhere in the RPM range. Part throttle, full throttle, idle, valves open or closed, no drone. So the CMS Ultimate sounds awesome when you want it to but doesn't drive you nuts when you're just cruising.

The dual-outlet design uses the same scavenging principle used in racing headers.  At high RPM, each exhaust pulse creates a vacuum in the opposite outlet, "pulling" the next pulse through to increase velocity, reducing back-pressure and pumping loss, and increasing horsepower. At lower RPM, this effect is less prevalent, allowing mid-range torque to rise as well. 

The CMS Ultimate design also allowed us to relax the radius on each curved outlet pipe, further improving high-RPM flow.  Our unique design eliminates the need for a power-robbing, flow-killing cross pipe to eliminate exhaust drone. Instead, the CMS Ultimate GT3 exhaust makes power and sounds incredible across the rev range.

Each exhaust is meticulously crafted from the highest-quality 304 stainless steel available, the result of our unwavering focus on workmanship, design, and premium materials. The CMS Ultimate GT3 exhaust comes with an ultra-high temp 2000°F ceramic coating in satin black, satin silver, or satin bronze.

As always, we only sell products that stand up to our punishment on the street and at the track. If we don't use it, we don't sell it!  With that in mind, the CMS Ultimate GT3 exhaust is backed by our Love It Or Leave It Guarantee: install it, drive it, if you don't love it send it back to us for a full refund.*



  • Designed and manufactured in the USA using premium American T304 stainless steel
  • 30-degree slash cut dual 4.2" outlets
  • Exhaust-scavenging cross flow for superior performance and sound
  • Relaxed-radius four-inch outlet pipes
  • Your choice of satin black, satin silver, or satin gold 2000°F ceramic coating
  • Premium AccuSeal exhaust clamps included
* Within the first 30 calendar days from the date of delivery.
Write Your Own Review
You're reviewing:CMS Ultimate Center Muffler Delete 991.1 & 991.2 Porsche GT3/RS/911R
Your Rating