It's a little different for the 94-98s; the GT exhaust was designed to go under the flat bumper.
If you get a kit, ask if the kit is designed with the flat or the cut-out bumper in mind. I got a GT bumper to replace my old, punctured stock one, and the Borlas I got are designed for the flat bumper. So now I have a big gap between the bumper and the tips.
If you get GT take-offs, you will definately have to get a GT bumper, or redo the tailpipes. Other aftermarket catbacks may be designed to go under the stock bumper.
Please don't just cut the bumper; I've seen it and it don't look right.