This HKS catback was developed to improve your torque and horsepower with a great deep throaty sound. Adds HP and increased throttle response. Piping is mandrel bent with a stainless steel muffler and includes a bung for the 02 sensor. Sound: Low deep growling sound. Provides a loud tone under acceleration, moderately quite at idle. TECH TIP: Direct bolt on, includes EVERYTHING for an easy installation. NO other modifications needed. Bolts up to the existing stock exhaust hangers.