If you already own the car and are emigrating and have a visa then its a straightforward process and you can get a exemption from the normal aussie import rules, under the personal import scheme.

Basically you can take in whatever car you like as long as you have owned and used it for a certain period in the UK first.

Depending on the state you want to register it in then you may have to make some small changes, just check with them direct, you should find all the info on google

Costs about £1500 to ship in a dedicated 20' container from the UK.

Budget about 50% of the cars value in import duties etc though, as they like to screw you for that, its based on the purchase invoice, and reduces depending on how long you have owned the car.

If you have not bought one yet, then find a car with aircon, its a must over there.