There are a few websites - usually importing broker websites - such as J-Spec, SSVI, etc that show and list cars for sale at auction.

Once the car arrives (what ever it may be) first thing after it lands and is released from quarenteen is compliance - this can take upto 4 weeks (sometimes alot longer). Once the car has been complied and you have your compliance documents and compliance plate on the car - THEN you can register it over the pits.

Be wary though - that if you are registering a car for the first time in WA - and it has never been registered anywhere in Aus before - it MUST be completely standard. I found this out the hard way (NB: this is only for cars not imported under the 15 year rule - so newer cars)

Hope that helps alittle

D