The part is used to bypass the catalyst from the exhaust to create a decat system. Eliminating the catalyst enhances gas flow and performance by removing the restriction caused by the catalyst, resulting in a significant increase in horsepower. This product is intended for motorsport use only and requires a Stage 2 ECU remap. - Bypasses the catalyst for improved exhaust flow - Designed for motorsport applications - Significant horsepower gains by removing catalyst restriction - Manufactured in the UK and distributed worldwide Specifications: - Pipe Diameter: 76.20 - Fitting Time: 3 to 4 hours (including removing OE system) - Race Product: Yes - EMarked: No Kit comes with: - LH Decat Downpipe with Heat Wrap Protection - MSAU734REP - RH Decat Downpipe with Heat Wrap Protection - MSAU735REP Vehicle Compatibility: - 2018 and later Audi RS4 B9 2.9 V6 Turbo Avant (Non OPF/GPF Models) - 2017, 2019 Audi RS5 B9 2.9 V6 Turbo Coupe (Non OPF/GPF Models) - 2018, 2019 Audi RS5 B9 2.9 V6 Turbo Sportback (Non-OPF/GPF Models) - 2019 and later Audi RS5 B9.5 2.9 V6 Turbo Coupe (Non OPF Models) - 2019 and later Audi RS5 B9.5 2.9 V6 Turbo Sportback (Non OPF Models)