you could hollow out the cats but you would probably get a CEL since (correct me if im wrong) you only have 2 cats... whereas my car has 4 so I just removed the last one on each side. and would get the same effect with putting in pipes...
but for me no check egine light, of course I left the O2s in (that would have lead to a CEL for sure) and also it some got rid of an aweful drone that I had.
