Keiran, I brought in a 65 out of Seattle WA, and had it shipped by an Adelaide company, and it was an easy process, it cost me $2400 AUD + the GST of the cost of the car and the freight, which was next to nothing. Nothing else to pay, all the import approval done, customs cleared, AQIS inspected and cleared.
As long as your car is clean and passes the AQIS (Quarantine) inspection, you will not have to pay anymore. The whole process was easy, and I will surely use him again when i ship my next one back. I brought my car in December (late)and had it in Brisbane by early March.