While the factory rear muffler on the standard 718 GT4 wasn’t a major restriction, reusing it on the high-performance GT4 RS has created a bottleneck for the GT3-derived engine. The original tubing diameter—less than 2¼ inches—remains unchanged, restricting the increased power output. Although this design helps meet sound regulations and simplifies manufacturing, it doesn’t maximize the performance capabilities of the GT4 RS.

Our Valved Exhaust system changes the game by utilizing full 3-inch oval tubing, perfectly engineered to fit within the tight confines of the rear chassis. With a focus on performance and sound quality, we’ve designed the secondary flowpath as a Helmholtz chamber to effectively reduce drone, ensuring a smooth and enjoyable driving experience. Coupled with our Valve Controller Kit, you can maintain optimal sound and performance throughout the rev range, unleashing the raw, unmistakable tone of the flat-six engine as you push it to its limits.

Internally the SOUL muffler is quite unique. It has little to no restriction in the flow path, using straight through piping that is perforated to allow exhaust gasses to escape and become muffled in the surrounding packing material of the muffler body. We incorporated a second internal X-pipe to allow the exhaust flow to merge smoothly. These characteristics combined were crucial towards reducing and smoothing out the drone in the 1,800-3,000rpm range while enhancing that higher pitched note we were after in both the valves closed and open conditions.

HAND-CRAFTED CONSTRUCTION

Mandrel bent, durable .065″” T304L stainless steel tubing

Bespoke, high endurance SOUL X-Pipe muffler designed to reduce volume without reducing performance

Back purged TIG welding (with ARCAL™ Prime argon gas) ensures proper weld penetration for exceptional strength and longevity

Water jet cut brackets are made to ISO 9001:2015 standards with ultra-tight tolerances of +/- 0.003 inches for extreme precision

Fabricated using thick-gauge aluminum fixtures that act as a heat sink during the welding process to prevent any warpage

BOLT-ON AND GO

Every component undergoes rigorous quality control and is fixture-tested to guarantee precise fitment. After passing QC, each exhaust is foam-packed to ensure it arrives in perfect condition.

BACKED BY LIFETIME WARRANTY

Enjoy your SOUL exhaust components with confidence on both the street and track as they are covered by our Lifetime Warranty! Our team will quickly work with you to resolve any issues or answer any questions that you may have.