the 2001 That I just bought already had the vararam/longtube header/corsa exhaust on it. I haven't been able to race a stock c5 yet to see the diffrence, but it sure does a modified mustang GT and a new lancer evo look like they arn't moving. The guy who owned the car before me was a mechanic, and said between the intake and long tube headers, it took a long time to install, due to its routing.