Is there a tremendous difference between oem cat converters and high flow cats? I know there is differences in various setups, Im speaking in terms of my puny NA D16zzzzzzzz6. I want to get a cat because im tired of my 3ARacing fart can I have now. No cat + $100 AutoZone Muffler = ticket. SO im looking to get a cat, (oem or high flow) and prob an Apexi world sport exhaust or a Flowmaster 50 series or something similar. PEACE EASY