Mitchy is 100% right...when I got a yellow for height, the guy at the pits (east perth) listed a heap of things i needed permits for, including BOV, strut brace, pod filter. Failed for still being too low...and an apparent locked diff. So went to pits again (welshpool) and they guy there laughed and basically called the east perth guy an idiot for listing some of the things needing a permit, like the pod and strut brace, but still gave me permits for them, and the diff passed fine.
The BOV was totally atmo (Greddy Type S) and I got a permit for that too although at the moment there isn't one on there at all since the power upgrade
Cheers,
JB