The problem is finding wheels in our 4x114 lug pattern with a high enough offset. Most manufacturers seem to make them in the 40 or 42 offset, but 45-48 would be more ideal. I've had two sets of 18s, both with 45 offset (18x7.5 with 225/40s) and with uncorrected camber and a 1.5-1.75" drop I never rubbed. Under suspension compression the wheels and tires cleared the fenders and were able to tuck without rubbing (esp in the rear where most people have the problem).

Then when I corrected my camber in the rear only, I did rub on the rear bumper tab and slightly on the fender itself. So I dialed the camber to right on the spec limit, that combined with grinding some plastic off the rear bumper tab basically alleveiated the rubbing to now it's only occasionally, only under a hard corner with passengers in the back, or a big smooth bump in the road driving over 30 mph, etc.

All rubbing could be eliminated with rolling the fenders.

So the answer is: 48 would be ideal, 45 is better, 42 is liveable (a lot of my friends have them) and 40 I'd avoid unless you are willing to roll your fenders.