I might suggest doing a lot more research before making your mind up either way rather than listening to just one opinion.
Don't get me wrong, GSTs are great for roll racing and that is about 80% (or so it seems) of the local racing here.
BUT, the idea that GSXs don't have any real advantage until you are making a lot of power is misguided. A stock GSX will still have a huge advantage when racing from a stoplight. There are several local people who have had GSTs and gone to a GSX because they were sick of not having any traction.
Talk to Stoli. He has a GST Spyder, and although it is a beautiful car, wheelhop is not his friend. Also talk to Todd, who has had both and is looking for his third and refuses to go back to a GST and the same with Brian Wilson who has just gone from a GST to a beastly GSX.
Just make sure you make a decision you will be happy with. One of the things that make our cars unique is thier AWDness.
Also, if you are making power, you have to worry about the tranny if you are FWD OR AWD. Wheelhop in a FWD is not tranny friendly.
I would suggest starting here on dsmtalk and search for the 1000000 threads on the subject. Feel free to ask me of any of the locals if you have any questions and I am sure that everyone here on this board will help too. But searching is better as if you are asking a question that is asked 100 times a week (Which is better AWD or FWD?) you will sometimes get snapped at with a use the search button! response (good idea anyway).