well thats what i did...after my cat cracked, i simply cut it out, and i welded a straight pipe on which i got from home depot.
the issue i have with this is the fact that its not perfectly straight and is pressing pretty hard against the body where it bolts on to the muffler. this produces vibration and a very loud (and a bit ricey) vibration between 2700-3000rpm. i think ill just wait and see....ill either get so annoyed with the vibration that ill just take it off and make it straight with a hammer
or just take the cat off a parts car im getting from a local insurance auto auction
probably wont opt for anything aftermarket unless i find a really good deal on ebay or what not.