The STILLEN 350Z exhaust, crafted of Mandrel-bent Stainless Steel, is a True Cat-Back System designed for long service life, and helps the Z pump out an incredible 13 additional horsepower at 5600 RPM and 14-ft.lbs. of torque at 4500 RPM. At idle the STILLEN Exhaust is unobtrusive. However, when the pedal gets pushed, it comes to life with a recognizable “STILLEN” trademark sound. It’s a sound especially associated with big horsepower & torque gains for the Z.