If you order a cat-back exhaust for a V6, you will get a Y-pipe cat-back
If you get the gt H-pipe, you can order any GT Cat-back system.
V6 cat backs are specifically for the V6 stock exhaust system.
So, get the GT H-pipe, then order a set of GT Cat-backs
A lot of us have GT takeoffs, which is the stock Cat-back off a GT. So, if a stock GT takeoff fits our cars with modified cat pipes, and GT Cat-backs fit GT's, then they will also fit ours with a modified cat-pipe..
Now, by modified Cat I mean
My Stock catted Y-pipe was cut and had a pacesetter H-Pipe welded onto it so it's the same as a stock GT H-pipe..
The Stock GT H-pipe should fit your car then the GT Cat-back exhaust will bolt to that..
I can't speak to whether a GT H-pipe will fit though. Any decent muffler shop can install a GT-cat back on your existing catted Y-pipe by fabricating an h-pipe out of it.
Can't afford Mods? Go To College!