Get a plan and a budget together. No use having one without the other.
THe GT brakes are much better than what you got. Yours are 10", my 89's were 11", the 95's are 12" (I think), and the M2300K Cobra brakes are 13". I got the 13". Great "investment" (yeah, its a few bucks, but you get what you pay for).
Hunt around for rims. Cobra wheels are about as common as belly buttons, everyone's got some...
Tires are more opinionated, and wont open taht can of worms. As I literally dont own a pair os street tires, I cannot comment.
Start slow, plan each move, buy from ONE manufacturer for all your parts. Psersonally I think Griggs is the best track-duty, but Steeda 5-link is pretty impressive too. FYI, My project has been going on for 7 years. ONE project per year: 16"-wheels/tires, then suspension, then supercharger, then 17"wheels/tires/brakes, then cage, then K-member and TKO trans (oops, that was unplanned when T5 broke).
This year.......... NEW MOTOR!!! WOOHOO!!!