Have you had a GTP before? It's real fun and easy to add some ponies, you'll love it. Add your modifacations, but don't spend all your money on those mods until you check a couple of common failure points on these cars. Trust me, it's no fun to beef up your ride and then have something like the transmission dump out because you never thought to check it! So...
It's been sitting a year and has 94k on it, you'll at least want to check the following:
* Failure of the lower intake manifold gastket (LIM), by this time it may be leaking coolant internally or externally, which left un-adressed will destroy the engine. If your car still has the orange Dexcool coolant in it, you'll want to change that out, too.
* Have the transmission thoroughly checked out, scanned (do NOT flush it, too risky if they don't know what they're doing). It's safe to say that our 4T65e-HD tranny's require meticulous attention. Start using Dexron VI tranny fluid, learn how to change it yourself, and replace the transmission filter every now and again.