I guess 20 to 21 fits perfect in addiction to the width. For example, a 21" Wheel with 8.0" width doesn't look very cool. But the question is, how wide can you go with standard chassis or with a lowered one instead.
@YetiSepp Actually, I am going to install air lift suspension on my car. Recently I discussed with guy who will help me out with that. I was thinking of choosing 3 options:
1. To lower car with H&R springs -25mm
2. with coilovers 35-55mm
3. Air lift sistem
So №3 option is more all-purpose sistem. I can lower about 50 mm from ground clearance 190 mm and raise 50 mm till 240 mm.