i got flowmaster 40 si/do... if I dump the exhaust... like curve down right after it exits the muffler... that will change the sound make it louder? also... I have 2 Cat converters... If I was to cut 1 of them off... would there be anything bad along with that? like check engine light... or illegal? or anything along those lines? :P

 

dumping the exhaust will make it deeper, but not as loud as if you left it coming straight out of the muffler. You can probably get away with cutting 1 of the cats off.