Milltek Sport Large-Bore Downpipes are designed to improve both performance and sound. These downpipes feature a larger diameter compared to standard OEM parts, allowing more exhaust gas to exit the engine and pass through, which increases efficiency. When used with the Catalyst Bypass Pipe, significant power gains can be achieved without restriction from a catalyst. All Milltek Sport performance exhaust systems are manufactured in the UK and distributed to over 90 countries worldwide. Note: This product is intended for motorsport use only and requires a Stage 2 ECU remap. - Larger diameter than OEM for improved gas flow - Designed for increased efficiency and power - Manufactured in the UK Specifications: - Pipe Diameter: 76.20 - Race Product: Yes - EMarked: No Kit comes with: - Large-bore Downpipe and Decat - MSBM253REP Vehicle Compatibility: - 2012-2015 BMW 3 Series F30 328i M Sport Automatic (without Tow Bar, None xDrive, N20 Engine Only) - 2014-2016 BMW 4 Series F32 428i Coupe (Automatic Gearbox, without Tow Bar, None xDrive, N20 Engine Only) - 2014-2016 BMW 4 Series F32 428i Coupe (Manual Gearbox, without Tow Bar, None xDrive, N20 Engine Only)