Whether it's too big or too harsh a ride is a matter of personal opinion.
if you get the offset correct then a 17" wheel / tyre combo won't rub at all. It also depends on the profile of the tyres. I don't mean the 40 ratio, but the physical shape. Avon and Toyo have quite a rounded edge to their tyres, where as Bridgestone and Michelin have quite a square corner. This matters as it could be as small a difference as that which means rubbing or not.
You're more likely to get rubbing on a lowered car too. But then 17s on a non lowered car looks a bit weird to me.