That's like a real dumb idea. You don't even see any real gains from hollowing out a stock cat. Ok, maybe 1 or 2. No more than 5 hp max depending on the size of the exhaust bolted to that said cat. Your best bet is to build a custom exhaust with an unboltable straight pipe/cat so you can still pass emissions instead of getting a MIL code of a P0420 or P0430 (catalyst efficiency). Unless you actually like paying for that. That's a waste of your money and time to tear up a perfectly good working part only to be maybe 1/32nds of a second faster to 30 mphOriginally Posted by SLo_MKIII