Our GT exhaust system for the BMW E63 M6 offers aggressive race car sound and performance. Made of high quality T-304 stainless steel, our GT system shares the same design as our ST street system with the exception of no catalytic converter. Expect a 10-17whp gain and a weight saving of over 50lbs from the stock system (stock: 122 lbs vs. RPi: 59 lbs).