mate get the decat straight thru to a nice 3" tailpipe and backbox, but leave the baffles in the backbox and u should have a lovely noise mate, if u take the cat out cut it off your old exhaust and trim, weld on exhaust brackets at both ends ans same on new pipe (aart from cutting cat off just cut a slot out), stick a gasket in the middle of the brackets and kaboom ... bolt on bolt off cat 5 min job before mot's :D take it for a good run out before going to the garage tho!!... btw u will get a engine management light when u take cat out after about 20 miles.. i poo meself and didnt drive it until i got it into a garage and he just put a £5 sensor in and the light went off :) hope this helps.