It would sound better, but the stock mufflers should go too if you are getting a new midpipe. Just get 2 new mufflers put on at the same time too instead of paying 500 bucks for a whole new cat back. As far as X-pipes, SLP makes good hi-flow catted ones, and the design of the junction is similar to that of Dr. Gas, which is probably the best. I have SLP, and it fit real nice with good clearance and a killer sound.