ok guys, ive been wanting to do a gutted cat for ages now, but i didnt want to do it unless i had a spare cat just in case i ever needed to put it back on (i remember glanzajim having huge troubles trying to get his thru mot and ended up putting one back on) so ive recieved my cat downpipe this morning, but im undecided on what to do now. initially i was going to gut the cat downpipe i got thru the post, but now i keep thinking im gonna do it and then find taking the old one off the car a total pain in the arse especially with sensors and what not, so should i gut the one thats on the car ins