Eagle Muffler on the East side does custom work like that. They welded a cutout and a few O2 bungs on my car and I don't have cats. The guy that does it is into circle track cars, cool guy, name is Mark.
BTW - Do you really have a 2001 SS thats SOM in color? If it has chrome 10 spokes, a 6 speed, T-Tops, leather and no traction control, I know that car, there is a story behind it.
Bill