OEM catalysts are often very dense and restrict 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. This product requires a Stage 2 ECU remap. - Reduces restriction over OE catalysts - Allows for improved exhaust gas flow - Designed for performance applications Specifications: - Pipe Diameter: 63.50 - Race Product: Yes - EMarked: No - MSCAT01: Universal Catalyst (200 CPSI EU4). 108 DIA x 250 LG - 63.5 ID - MSCAT01