when i first put my 20's on i also had loba front discs fitted at the same time.
i didnt really feel the extra heft of the 20's cause i guess the weight saving on the discs was somewhat canceling out the extra weight of the bigger wheels and tyres so it didn't feel much different on the road, a bit firmer maybe but i was happy with the overall feel.
however having now gone back to my original 19" inch wheels the difference in feel is very noticeable, the steering is lighter with more feedback more adjustable the handling just feels better.
i have done both and prefer "feel" over "looks", plus tyres are cheaper as well lol.
