3.1 v6 dual exhaust system

hey, i have a bad cat convertor on my car, just wondering what, if anything, is out there for a better system becuase if i'm replacing the cat i am considering just doing the whole system while im at it, and i fuigure i might as well upgrade it at the same time. I am looking for something that will give it a little extra kick and a nice deep sound at the same time? anythign available out there?
also i want to keep the stock pipe tips or get something with a simmilar look because i like the way the 4 outlets look.