The factory rear muffler wasn’t much of a restriction on the standard 718 GT4, but reusing it for the GT4 RS has created a bottleneck for the GT3-derived engine. The tubing diameter remains the same, meaning that increased power is now forced through tubing that measures less than 2 ¼ inches. Repurposing that muffler helps meet sound restrictions and eases manufacturing processes, but doesn’t extract the most performance out of the GT4 RS.

Our Valved Exhaust uses full 3-inch oval tubing to fit within the envelope provided in the rear of the car. With the expectation that most customers will prefer driving with the valves open, we’ve tasked the secondary flowpath to act as a Helmholtz chamber to reduce drone, and our Valve Controller Kit can maintain this throughout the rev range, while releasing the ultimate expression of flat-six tone as you wind it out.

FITMENT: Due to the unique design of the anti-drone features, this system will NOT fit with factory Over Axle Pipes. It must be installed with any of our Over Axle Pipes, or other aftermarket options.