aFe Power's Twisted Steel header for the Scion FR-S / Subaru BRZ / Toyota 86 produced a max gain of +10 horsepower and +13 ft. lbs. of torque verified by our in house dyno. aFe spent countless hours of R&D to develop the perfect balance of pure, race-inspired performance and sound with zero drone. The headers are constructed of near equal length mandrel-bent 1-5/8" 16-gauge, 304 stainless steel tubing and uses thick flanges for added strength and to ensure a leak free seal. The smooth curves and increased diameter of this header helps remove restriction and keeps exhaust gas flowing smoothly for improved performance and response. To eliminate dead space that can cause turbulence and hinder flow a 4-to-1 formed collector and optimized tube lengths are used to help increase exhaust velocity improving flow, torque and throttle response. Incorporated in the header is a 200 CPSI, 48-state legal catalytic converter and includes all components for a hassle-free installation with no modifications necessary.