I had 16s but went up to 18s really fill the wheel arches nicely. My 16s made it look like a beach buggy!
I have news for you, if you fitted the correct tyres the wheels are exactly the same overall diameter as the 16s. 255/65/16, 255/55/18, 255/50/19 and 255/45/20 are all the same. They will all fill the wheel arch equally.