Dont lose Ford's factory passenger side manifold/ hpipe gasket or it will leak horribly. My friend just put a MAC CAI kit and catback on his car/ o4GT and it sounds wimpy. Not much more sound than with stock musfflers and pipes, waste of money really. The true fit balled flange tailpipes wont even line up right out the rear bumper. If the Hpipe is of the same quality as the Catback, good luck.