I'd go with 17s, 18s if a must and try to avoid the 20s.

After 18, the "value" of the bigger wheel starts to become no value at all. The increase in unsprung weight negates any handling advantage. The tires are really expensive. Rim damage is certain when the potholes bloom.

IIRC, certain desirable option packages "require" the 20s, so good luck on that front.