I basically agree with TTA89s comments. The TTA squeaks and rattles a lot to me, something I do not care for all that much. Plus, the GN is much smoother in every way. But the TTA's performance (assuming both are stock) is quite a bit better in my opinion.
I bought a 94 Firebird Formula (LT1 6 speed with T-tops) and found that car to be 1000% better in the ride quality/no squeaks and rattles dept than the 3rd gen Fbody.
Both have their pluses and minuses. I love those form-fitting TTA seats, and hate the junky GN ones. Overall, I'd take the GN though, especially if I drive it much at all.