Yoshimura Offroad RS-4 94DB Stainless Aluminum Full System Exhaust for 2010-201 - One Size The RS-4 is a unique design with predicated power, a side benefit of a quiet earthy exhaust note that speaks volumes for performance and offers increased horsepower and torque. It feature a polyresonant duplex chamber A 2-staged stepped baffle and an innovative carbon cone end-cap.