One idea man, why not buy an R34 GT-T that someone else has spent the 20k on it, save yourself a tonne of money and means you dont have to go through all the effort of getting your car setup.
I would personally buy this:
http://www.skylinesaustralia.com/forums/19...amp;hl=EAST+kit
The other question you have to ask yourself is do you want the car to appear legal? If so, you want to stick to a hi flow turbo, go big cooler and keep the stock airbox. Exactly like the car above.