In syd, my friend got a ticket for not having water in his wiper reserve tank !!!
there are ways around mods though,
you can hide things like turbos, ecu, BOVs, best place for a BOV is under a fender. I think people usually get booked when an officer has lots of shiny things to look at. Shiney stainless steel piping, blue silicon hoses are a good sign of something else sleeping under the bonnet.
To be honet, i much prefer the stealth look, i have black intercooler piping, black BOV, black Boost controller, ecu is hidden, BOV is under fender, black runners surrounded by black heat sheild,
next thing on the list, black rocker cover. Its still all there, but its not staring you in the face is all im saying.