Maximum flow is essential to any turbo charged vehicle. The stock exhaust diffuser is very restrictive and not free flowing. The BLITZ Exhaust Diffuser was design to free up tohe exhaust flow by removing the main catalytic converter. With the increased flow, the turbo will respond and spool up quicker. The BLITZ Exhaust Diffusers are constructed of one piece cast iron or stainless steel and utilzes all existing brackets and will retain all stock heat shields. (Use With SR20DET Only)