Micah,
Whats up man, my car was parked next to your buddys cougar at HIN.
The RA gearset probally isnt going to be enough, you might want to think about a dog box or maybe a helical cut gearset. The STI Tranny might hold up but, the gear ratios suck, with a PPG gearset you can get what ever ratios you want.I can get you a good deal on a gearset through Batlground and Gearboxtech.com.
Your car will be a beast with the 2.5, gt30r, and a good gearbox. HOLD ON
If you stop by Batlground this week I will probally be there, you can check out the car etc..
Matt
edit:
I see you are in NC. The next time you are down this way, give batlground a call, They know my number, Ill be happy to bring the suby by the shop so you can check it out.