OEM catalysts are often very dense and restrictive to gas flow. The Milltek Hi-Flow Sports Catalyst reduces restriction compared to OE catalysts, allowing for a freer-flowing exhaust system to improve engine performance. - Reduces restriction over OE catalysts - Allows for free-flowing exhaust system - Designed for a wide range of vehicles - Manufactured in the UK Specifications: - Pipe Diameter: 70.00 - Race Product: Yes - EMarked: No Kit comes with: - MSAU636: LH Hi-Flow Sports Catalyst (under-floor) - MSAU637: RH Hi-Flow Sports Catalyst (under-floor) - MSAU663: LH 76mm Primary Cat Bypass Downpipe (fits LH Turbo) - MSAU663 - MSAU664: RH 76mm Primary Cat Bypass Downpipe (fits RH Turbo) - MSAU664 Vehicle Compatibility: - 2013-2018 Audi S8 D4 4.0 TFSI quattro Tiptronic