aFe POWER's Twisted Steel Headers are constructed of 1-5/8" 16-gauge 409 stainless steel tubing with 3/8" thick CNC Laser cut flanges to ensure a leak-free seal. To eliminate dead space that can cause turbulence and hinder flow that formed s are prone to produce, a mitered merge and optimized tube lengths are used for true pulse control technology improving flow and performance. The smooth curves and increased diameter of this header helps remove restriction and keeps exhaust gas flowing smoothly for improved performance and durability. All components are supplied for a hassle-free bolt-on and go installation with no modifications necessary. 3-to-1 mitered merge decrease turbulence and increases exhaust velocity. The result is increased horsepower, torque and improved throttle response. Tube lengths are optimized for true pulse control technology which improves flow and performance. Flanges are CNC laser cut not only to be visually appealing but for a durable, precise fit and leak-free seal. These headers are constructed of durable CNC mandrel bent, stainless steel tubing for maximum performance, corrosion resistance and strength eliminating cracking. Each header comes with 300 CPSI (cell per square inch) metallic high-flow catalytic converters for maximum flow. This performance header is designed to fit in the stock location no cutting or drilling required making it a true bolt-on and go solution. This kit also includes a gasket set and all necessary mounting hardware for a hassle-free installation.