Umm,
being a member of multiple forums, something on this often crosses my path. It seems once a car has been engineered and registered in one state, then the others honour the engineering. there is much talk of QLD's ridiculous LO2 compliance requirements, but cars previously registered in other states are honoured.
As for an engineer in in melbourne, I suggest Archie Robinson in Bayswater. He can be pretty anal, but you'll get an honest assesment. I dont have his number but the vic pres will.
Cheers
Jas