I'm in the US and I can tell you that it is impossible to legalize vehicles from overseas. You have to go thru all the emission test and safety test (ex. crash test, etc) which doesn't make sense at all. I was once tried to import two stroke bike (it's illegal unless 50cc) and I found that it was impossible.
If it was easy to bring cars here, you would see skyline/JDM cars everywhere. All I seen around here is the engine swap from JDM engines or clips.
Why do you want to go through all the hassle? Reason I'm saying is car is really cheap compare to Australia. For example, you can get new 350Z base model for $27k USD or new M3 for around $47k USD.