Gears and a tune. For the money you wont have any more fun then that. You should have a few dollars left over for a short throw shifter as well.

 

He already has gears and a tuner.... +1 on the pi swap that would be first on my list with a nice cam. depending on how much you spend on that tubes and the TB would be next down the road. Not really sure what your plans down the road for the car are so that's just my .02 for now. If you start lookin into the swap I have the pi intake for $100 shipped, 3000ish miles on it, thermostat included.