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 free-flowing exhaust system to improve engine performance. This Hi-Flow Sports Cat is supplied with a downpipe, designed to improve gas flow and maximize the effect of the sports catalyst. Note: Requires Stage 2 ECU remap. - Reduces restriction compared to OE catalysts - Includes downpipe for improved gas flow - Designed to maximize exhaust system performance Specifications: - Pipe Diameter: 70.00 - Race Product: Yes - EMarked: No Kit comes with: - LH Primary Downpipe & High Flow Sports Cat - MSBM242 - RH Primary Downpipe & High Flow Sports Cat - MSBM243 - X Pipe - MSBM244 Vehicle Compatibility: - 2007-2011 BMW 3 Series E90 M3 4.0 V8 Saloon / Sedan - 2007-2013 BMW 3 Series E92 M3 4.0 V8 Coupe - 2007-2013 BMW 3 Series E93 M3 4.0 V8 Convertible