This is an attempt to link the relevant departments governing design standards and the limits of modifications, both owner certified and engineer scrutinised.
ADR (Australian design rules) are obviously a national standard pertaining to lots of things, but each of our states has its own dept which has a secondary set of rules which is specific to each state.
Maybe those from other states to NSW can link the relevent motor traffic dept websites.
Third Edition Australian Design Rules.
Read the page and follow the links to find the applicable ADR.
NSW vehicle standards information sheets.
Pertaining to owner certified mods, replacement wheels, window tint, noise, ground clearance and all those area's that may become grey when we start messing around with what the factory set.