First, I like a "sporty" feel, which may also translate into not really liking soft riding feel. However, I drove the stock ones for a few hundred miles and am pretty sure the 20's, mainly the 1.5" wider rubber on the ground, makes for cornering with more assurance. Stopping distance/grip also seems better because of the contact patch being significantly bigger. Lastly though, the Toyo Proxes ST is so much a better tire than the goodyears are, it's several things improving the overall.
Shorter sidewall reduces the "woblyness" of the lr3 handling, just like in a car going from 16's to 19's.
I would guess that the air suspension takes care of any adverse "ride-feel" gained of the lower profile tires.