You need fuel injectors, fuel pump and a Unichip at least to run a VF22 to max capacity. Obviously race fuel is mandatory. Boost pressure means nothing. It's HP capacity you're looking for. I believ it is worth 360 hp or so but it is super laggy. Try a VF30 instead or a PE1818F. Much better choices. The PE1818F is 400 HP capable.
That is correct although the difference between the two is very small. I got the 1818 because I ws the one of the first to get one and it seemed like the better choice for me (drag rcer extrordinaire I am not). Remember they both have the same flow rating, just different housing is all. I'm pleased with it but for the STi project I will be using an HKS GT3240 600 HP turbo.
Ah yes, the HKS kit. Of course. That is available no problem. I have all the piping and flanges necessary. Just need to order the turbo and external Tial wastegate and we can install. We can go with a 480 HP 3037S or perhaps you would like an HKS GT3240 600 HP model? I'll be using that one on my STi when it comes in.
I actually have one from a customer who is wanting to trade it in on an 1820. He is selling it for $1450 which is less than even group buy price. I highly recommend this turbo. I am incredibly pleased with mine. Decent spool up and kills the VF30 on top end power.