+1 @SHELL
if its only guna cost ya $200 then id do it now and get it changed back after the rego side of things is sorted.
-exhaust needs to be <90dB @3,200-3,600rpm (depending on date of build)
- no bashed out cats or de-cat pipes (big fines)
-pod needs to be secured and have some kind of heat shielding
-bov needs to be 100% plumb back and not adjustable
-intercooler needs to be securely mounted and centre section of bumper bar cant be completely cut away
-cant have a boost controller or bigger turbo
-coilovers are legal if they are set to correct ground clearance and eyebrow heights (usually marked so they can see if they have been messed with in case of a defect etc)
-tyres need to be load rated
-wheel spacers are illegal (any kind unless its an OEM fitted track kit)
-cant have external fuel pumps and big surge tanks in your boot unless its engineered
-no drift style handbrake buttons (no spring etc)
-unsure about anti-hicas bars
-no locked diffs
-if you have braided brake lines they must be DOT and ADR approved
hope that covers enough for ya