remember with >220kw comes tyres, clutch, possibly diff, also trans if running an rb20 item, fuel pump, injectors, metal intake pipe, full 3" exhaust, intercooler, associated piping, ecu.
It basically costs the same for 230kw as it does for 330kw, including turbo if the car is 100% stock I would put aside $4k+ for it.
Below 230kw all you need is a turbo, half decent exhaust, at least an R34 side mount, nistune or remap. Probably be $1k + 500 + 250 + 5-800 so ~$2.5-3k to do it properly, almost certainly will get shitty having crap tyres and the clutch will die fairly soon as well though.