Good choice with the Haltech's , i was thinking of getting a PFC for my R33. But i saw a Haltech group buy, and couldn't resist. I grabbed a E11v2 with 3 bar map sensor, and boost controller solenoid. It really all depends on how much you want to spend and what features you are after.
The platinum is more designed for the newer cars, such as R35GTR, so you are gonna be paying quite a bit extra for it. That's why i went with the E11v2, decent price and features, i also got the plug and play loom.