bigger radiator, FCD (fuel cut defender), better intercooler. Focus in reliability parts first...trust me. Eliminate as much heat from the engine bay as possable. A single turbo upgrade is the next best thing... 1) it gets rid of the rats nest of vaccum lines. 2)underhood temps drop significantly.

Once you make the car reliable, drive it mostly stock..maybe exhaust and some tuning... then start going big.