Depends on the wheels really for looks, but comfort is definitely a difference on oem suspension, I had my B6 S4 on stock avus 18's & was pretty good, in my wisdom (or rather not) one day thought lets get some 19's, exactly as above rs6 style, man that was a difference, also my S3 8L had 18's, tried 19's within 2 weeks swapped back to 18's & never looked back, another problem is decent roads, potholes etc where 19's will be more susceptible to buckles from personal experience
But if you dont care about comfort & just looks then 19's, if you want best of both 18's, down to personal preference at end of day really, so do what you want not what we advise you to, we only learn by our mistakes but yours to you might not be a mistake.
& think its 112 for 8P isnt it