18" for the summer with Falken 912's
and
16" for the winter with Hankook icebears
I just changed over last week and to be honest I though I would notice a bigger difference than there is. Last year it had Pirelli P-Zero Rosso on it and they were more harsh and wore down in no time at all. I didn't even think they gave particularly good grip so not worth the premium price.
The car looks soooo muxh better with the 18's and a little strange during winter as I have the AMG kit but I'm not bothered for the extra confidence the winter tyres give.
I love bigger wheels and don't mind the fact the ride is a bit harder due to it. I recently upgrade my ML alloys from 17" to 20" and too be honest its not that much different.
My wifes A class with 17's however does bump down any hole, I think its due to the suspension. Mine has that set for a Big American and just waffs over stuff hers has stiff uprated springs and is much harder.
Only other problem is you may want to lower it once you do it...
