If you plan on modding, do the exhaust first! And all of it! stock headers are restrictive as hell! some headers and a good mid-pipe will help the headgasket situation alot.
I had an 89 XR7 S/C 5 speed. Oh and track down a B&M Ripper shifter for that trans, the stocker WILL fall apart!
You do realize the OP's post was from 07 right?