Factory 4.1 exhaust is a great all-around pipe for your mini. The FMF Factory 4.1 Exhaust will give the mini racer one of the best pipes on the market at a reasonable price. Excellent power throughout the range, all backed by legendary FMF quality. The perforated steel inner cores make for optimum flow, using FMF's hi-flo technology. FMF's exclusive cross weave internal packing provides longevity and maximum sound disbursement