Aussie drivers are restricted for a couple of years after passing their tests. I'm not sure if it's different from state to state, but IIRC it's stuff like no forced induction, no V8s, power to weight ratio limits.
Mods are also restricted in Oz, unlike here, hence the defect notice for the car being too low. I think the minimum ground clearance is 100mm (4 inches). There are rules about the difference in wheel size from standard, and on the size of engine for transplants (no SB Chevy engines in Fiat 126s), for example, and stuff like the car has to have engineering approval if there is more than one modification to the induction system.
We really have it easy (at the moment).