Cut the cat out and save it. It's a expensive peice. Put a resinator in there. I run 2 resonators 3" but I'm turbo. It's a striaght though pipe with little to no restriction louvered/packed and calms the exhaust. It's like a straight through but calms the exhaust by 1/3 at most and bangs the exhaust wave against each other so it sounds cool. So again I run 2 resonator and a flowmaster 2 chamber on 3" exhaust, It's quiet when I cruise but when I hit it is sounds like a pack of mad bees. If you run smaller exhaust like 2.5" or below then run 1 resonator and a sport muffler your car will be tits
I'm saying people will look and not look like what the "f" is that peice of "s". They will be like "Holy Crap, that sounds bad"