The ultimate in Mini exhaust technology. The original manifold has four short primaries and a restrictive collector followed by two catalytic convertors in series. These catalytic convertors have cores with about 500 cells per square inch (cpsi) giving a flow area of approx 60%. The Quicksilver manifold and Sports Cat has four longer tuned-length primaries followed by a single free-flow Catalytic convertor. This Cat has a microscopically thin Fecralloy metallic core of 200 cpsi to which the essential Platinum and Rhodium are applied at a much greater density (25 grams per cubic foot compared to 10 grams on a typical aftermarket product). This all results in a flow area of approx 85% whilst remaining clean enough to meet emissions requirements. Key features include: Dyno tests show a 12 bhp improvement and increased mid-range torque. The Fecralloy metallic core is very durable, far more so than the ceramic cores typically used. This incorporates a triple-wall flexible section to a much higher specification than the twin-wall OE item - To allow for the greater loads imposed by a tuned engine. Accelerated gas-flow draws heat away more efficiently to reduce under-bonnet temperatures - particularly important for a tuned engine. The two original Lambda sensors are retained in their correct position for the proper operation of the OBD2 (on board diagnostics) system. Part # BM401. Click here for QuickSilver Tech Sheets