I actually have 2 questions. 1st ) How much does gutting the cat help with performance? and 2nd) How much do new DC Sports 4-2-1 headers actually help performance wise...?

 

ive been very tempted to gut mine too, im interested in the gains in both HP and MPG ?

 

dont do it... it wont help enough. inless your pushin some serious hp, then please dont.

 

gutting the cat should cost you a few HP, as it messes with the exhaust gas velocity. read the Backpressure article i posted a long time ago, it explains it very well. if you must get rid of your cat, get a test pipe, but the gains over a good high-flow cat are very small. as for the header, they usually show about 3-5 hp at the wheels. nothing ground-breaking, but very worth it.