Well I'm the opposite. For me it's either stock wheels, tuff 15's (like convo's or similar), or go big. Most 14"-17" mags I rekon look crap on any Commodore unless they are stock mags for that era of car. Ya see a Commodore with 17's on it, and it looks just like the majority of every other Commodore on the road, doesn't really stand out at all. I see a clean VB-VK with stock 14's and it gets my attention more then the same car with 17's lol.
We had 20's on my VK wagz, and that's without rolling the gaurds, no adjustable panhard rod and with lows all round. Rear end scrubbed a little bit over big bumps, but overall not bad. Also had 225's, anything wider and we'd prolly run into more problems. Did have to cut, lift and reweld the spring seats in the front to clear the tyres tho, only needed to be lifted a few mm. The 19's I had on b4 the 20's scrubbed a tiny bit with crap tyres, so will prolly have to lift the spring seat still, or cut a recess into the spring seat.