Thanks for the answers people. I know it's much cheaper to buy locally, but not for the car I'm after.. There are plenty of skylines around but none that fit my requirements and I'm not really prepared to import from Japan, although it would probably be cheaper. I suppose its the same kind of gamble you take when compared to importing because it can't be test driven, but I'd rather get a car interstate that has already been complianced and I know is working well (NRMA inspection or something similar) and pay the price for being fussy (or irrational haha)..
I did also read on the DPI website that you need a permit to move the car, and that it can only be moved to inspection workshops or to licensing centres because registration becomes invalid. DPI says you have 3 months to get your vehicle registered in WA after moving it from over east (but you still need a permit to drive it). Then again you see people all the time driving on different plates so who the hell knows!