Here's what I did to mine.
Turbo's (HKS GT2530's)
Oil Cooler
Intercooler
AFM's
Cam gears
ECU (PFC)
Brakes (Porsche GT3)
2nd set of rims + Semi's (driving round on semi's all day isn't cheap or fun)
Zorst
Tomi sump
adjustible cabmer and caster (i should have done the rest of the suspention, but I got other things to spend $$ on now)
Diff (mine was single spinning )
ended up with 311rwkw, and even though the suspention is average, it's consistantly round the top 1-4 in times at the track.
I've done most of the work myself though, dam you and your endless budget . If I had more $$ i'df done the engine, i'd recomend you do the engine.