A lot of basic parts ie pads, fluids etc, are readily available. Your local supercheap or autobarn should be able to get them for you.
As with any performance vehicle, the cost of the parts tends to carry a premium.
If the mod bug was to bite, then costs can sky rocket as upgrades tend to be sourced from Japan or the US. Let's just say that shipping companies enjoying using a nightstick to penetrate you in ungodly ways when calculating the cost of freight of large/heavy items.
Those are really high kms though!
You can probably look at something like this: http://www.carsales.com.au/private/details/nissan-skyline-2003-13324016?base=&vertical=Car&cr=19&page=2&eapi=2&__N=1247+1282+1252+1246+1216&num=15&silo=Stock&items=[Make:NISSAN,Model:SKYLINE,Series:V35]&sort=~Price
Get the guy to remove cost of rego etc, look at high 10s-ish, drive it to TAS and rego it there.
Edit: With any car, particularly performance cars, drop all the fluids when you buy it and give the system new quality fluids.