I have an 04.5 I was wondering if I just get HFCs for performance gain, sound, inspection, and all that good stuff... would it make the CEL light come on, as apposed to test pipes? Id RATHER have test pipes but dont wanna have to go back and put cats on to get inspect, and wouldnt want CEL light to come on just incase I take to shop, and it would annoy me anyway.

And what are some good HFCs on the market. I know what test pipes ill get if I decide otherwise but ive YET to look into HFCs at all

 

Crawford HFCs are top of the line. After that id prob. say kenetix.

 

No. High-flow catalytic converters ARE catalytic converters: they are simply not as restrictive as the OEM cats.