I like my Magnaflow :Cat: With the stock exhaust, the cat is noticeably louder, but not objectionable. Performance gains? Don't know - but the new one doesn't rattle, and that's an improvement. It probably does flow better.
For under $100 shipped from HERE I'd do it again. The "direct fit" one is a bolt-in replacement for stock - I picked up some stainless hardware from Home Depot.
Craig