Pfaff Pro Exhaust | McLaren | 650S | MP4-12CPfaff Pro Exhaust for the McLaren 650S and MP4 12c. Includes Downpipes and Rear X Pipe Engineered by Pfaff Tuning exclusively for McLaren vehicles, the Pfaff Pro Exhaust enhances the performance and acoustic signature of the McLaren 650S and 12C. This modular exhaust system includes downpipes with 200 cell primary catalysts and a rear X pipe. Used together, they deliver a distinctive, powerful sound as well as an estimated 40 horsepower gain at the