What Hybrid said, except you need the metal upper IC pipe to fit an upgraded BOV.

I would say do any maintenance that the car needs now. If the clutch is slipping, upgrade it, new plugs, Accel 8mm wires, etc. Basically replace anything that needs replacing.

Next would be the boost gauge and a pocketlogger. Though DSMlink would be my first choice for tuning on a 2G.

After that, SAFC (Unless you go with DSMlink), manual boost controller (Hallman like Hybrid said), hard upper IC pipe, and Greddy Type S BOV (cheap, reliable). Then downpipe and test pipe for your exhaust, and possibly 3" exhaust if you have some crap on there now :P.