think about WHY they have these rules and that should help you find an answer. vicroads' rationale is for cars to remain safe and roadworthy by not allowing monster wheels to be put on tiny cars, whose chassis/suspension etc wouldn't be able to handle it properly.
how similar is an r32 to an r35? chalk and cheese, but for the GTR label. i doubt very much you'd get away with it on that basis.
i go by the tyre placard, ie. 25mm wider than the widest rim on there.