When you say something along the lines like the one above, I will assume you want your Prius ride height to be similar to it. Well we can safely say that going any bigger than a 18 inch wheel with that sort of stance will cause rubbing. Width, can't go too wide on these, they were mainly built to be a A to B car. 9 inches wide is what i've seen the widest on a Prius
No really, have you measured your mileage after installing those wheels? I had no idea that the Prius had the same offset as an Audi !!!! Hope you got a great deal on those wheels, they are lovely to look at.