Ly, go to your profile and fill in your signature with what model you have! Too many cars here to remember them all, and the year and model make big differences in exhaust. Your exhaust choices are going to be different depending on what you're after. If it'* sound, changing the muffler will be enough. If it'* performance, you're really going to need to change the Cat, too. My Cat went bad right after I got my car in May......it sounded like the death rattle. I went with a performance hi-flow design, and had it custom installed so the joints weren't restrictive, either. The shop made custom flanges that were slightly larger than the stock exhaust, rather than slightly smaller, and the Cat is the same model that fit my 98 Z71. Larger inlet and outlets. I was amazed at the difference. I could feel a slight increase in power and the sound improved, too. I don't want obnoxious, but I love the throaty rumble.
There'* been more than a few suggestions to use the F body single inlet, dual outlet muffler. It'* more free-flowing than the stock mufflers on the SSE/SSEi or the SE. I've also heard that the Flowmaster has a different sound than the Dynomax, and they seem to be the top two choices that are talked about. After we figure out what model and type of exhaust you have, we may be able to compare some sound clips from cars already done to help you make your choice.