Some of us replace only the muffle and some of us go for the cat back. On a Crossrife the mufler is right at the end of the system and easily changed out. A cat back for a non SRT also gives you the pipe up to where it bolts on. There are only a couple of cat back systems available but they do allow you install yourself with no welding. on the other hand if you just replace the muffler you will have a much larger choice of mufflers but you will have to pay a muffler shop about $75 to cut the old one off and weld on the new one. For me I wanted a certain sound and look that I could only get with a universal muffler. After paying the $75, I was still well below the price of the cat back. IMO, all you get with the cat back is some identical pipe to replace your old existing piping plus a muffler.