Originally Posted by Fraser

The question of ride quality and wheel size is almost entirely dependent on your driving environment. If you drive on dead smooth roads you won't compromise ride quality by going from 18s to 19s or 20s. If however the roads are rough where you drive, you will compromise ride quality. Everyone's driving environment, driving style, and appreciation of a vehicle's appearance is different and that's why a question like this will always throw up a wide variety of responses.