Pretty much what Canuck said. Australia has it's own set of rules when it comes to vehicles and every vehicle needs to be tested and certified against them to prove that they will meet ADR compliance.

You can bypass these rules if you bring a vehicle in as a personal import. You must prove that you lived in that country of origin and owned that vehicle wihlst over there for a minimum of 12 months.

Once you go through the hassle of getting a personal import vehicle in, you'll never want ot sell it as you'll never get the financial value of it.

If you want to really buy a vehicle from Japan, then you need to source a freight forwarder, bring it over, and then source and already complianced frame to transplant all the bits into it.

It's honestly easier to just buy a vehicle that is already here in Aus, and then slowly build up the parts you need.

If you still think it is worth the financial cost and administrative hoops to jump through, good luck and let us know how you go