We put a Muzzy dual exhaust (full system) with a Dynatek ignition, K&N air filter and the EPI Sport Utility Clutch altogether in a kit that will leave all other stock Teryx guys cryin like a baby. You can also substitute the K&N filter for the AFE High Flow Air Intake kit and Stage II Jet kit in "Bundle 2" 32% HP gains and 6 lb./ft. of torque.