Well i bought my skyline a moth or so ago from melbourne, the rego guys in dickson are ****s, mine had boost gauge mounted onto the dash, they didnt seem to care about it, but they ****ed me up with the battery in the boot, (it was 4 days old), new castor rod bushes, they made me clean the underbody of the car and a few little other things. Watch out for the young guy , he is actually in charge there, i woulda passed if that guy didnt come along. but yeah i heard if u take it to Dunsters in Mitchell, theyll pass nearly everything, my friends have gone through them before.
but make sure u give it a good wash, give the engine a bay clean and the under body, if u have any obvios mods u might get picked on but other than that, try dunsters first its only 30 bucks, and apparently they are very lenient.