Before you go trying to unbolt the cat and get yourself all good and hot, put some heat to the nuts right before you try taking them loose. Don't do too much cause it'll heat the stud too, but if you can get just the nut a little hot it'll pop off a little easier. You should try just punching out the cat first, just to see if it gets better. If you go with a new one you can get a monolithic free flowing cat from magnaflow for pretty cheap.
