Welcome to Just Commodores, a site specifically designed for all people who share the same passion as yourself.
No its 2 inches bigger than the largest wheel stated on your tyre placard. So for instance on my VN I have a 14" wheel listed and a 15" wheel listed as 15 was standard on S and SS, optional on others.
Whilst my car came from factory with 14", as it says 15" on the tyre placard as well I can legally go to 17".
HSV's such as the group A had 17's, but that doesnt mean I can go to 19" as HSV's have their own tyre placard.
Also changing your tyre placard doesnt make a difference. The police still check a book for the wheel sizes anyway, so dont think you can get a VZ placard and stick it on a VL or something, as it is also an extra fine for changing the placard.
I have a VT with 20inch Mags on , cops drove by looked at it and moved on , i think personally its too low
I reckon you could fit 22" no probs
22 inch wheels WILL hit the strut mate and even with coil overs fitted I think you'll find you'd need to pump the gaurds to get it to sit right
the laws have changed alot since i was a tyre fitter lol