Australian ED XR6 Member
Join Date: Apr 2001
Location: Central Coast NSW
There is info on the NSW RTA site though they are somewhat difficult to find - I did a thread on this exact topic a whiles back now with listings to rta sites for not only NSW but other states as well - be aware that u also must comply with relevant ADR's as well. The NSW RTA covers issues such as vehicle mods & a stack of other "rivetting info under various Vehicle Standards Information sheets (VSI's)
Remember the basic rule of thumb if in doubt - ask a signatory engineer BEFORE you even think about the mod in question.