It would be hard for me to accept the weight penalty of 20's, unless I made my car strictly a show car. Aesthetically they look fantastic. If I could use a bigger series tire than a 25 aspect ratio with a 20, I'd be all over a staggered 19/20 setup as I sometimes think my Wilhelms appear small-ish from a distance. But, my ride height mandates an overall height of <26"... Hard to achieve with a 20" wheel unless you go with rubber bands for tires. And if you've seen our bridges...

18's are the best racer's setup, hands-down. Les (velociabstract) and several others have gone to a full 18" setup and the proof is in the times. Looks are subjective and while some like the mondo-huge wheels, others prefer that their form follow function and the meatier sidewall of running an 18" tire means better ET's and cheaper rubber. And a softer ride, to boot.

I stuck with 18/19 stagger because I bought some very spendy tires (see first post) and wanted to continue using those despite upgrading the wheels.

Down the road, I may upgrade to a 19/20 setup simply to change it up, as it is much more visually striking and I've tracked my car exactly 0 times in the last year.

So, an extra pound or two won't be a detriment.