My stock Chrome 20"x9's with 305/50R20 Terra Grapplers are about 90 pounds. Stock G/Y 275/60R20's are about 8 pounds lighter)
My Mickey Thompson ET Street DR's are 295/45R17's on Black Aluminum 17" x 9" Moto Metal 951's and weigh in just a bit over 60 pounds per corner (x4)
They actually measure out at about 27.5" tall x 11.5" wide.
Now there are several factors that come into play:
1) less weight, obviously
2) less rolling resistance, virtually no tread on DR's
3) less rotational mass (easier to turn a smaller diameter wheel)
4) Sticky compound will grab for a better full throttle launch and no spin.
5) lower ride height for better aerodynamics
(specially on 4 tires it makes my 2/3 drop look like a 5/6)
6) effective gear ratio reduction from 3.55 to about 4.30:1 (from stock G/Y's)
As a result, I'm about 5 tenths quicker,
track tested over 100 times each over the past year
305/50R20 Grappler's ... are good for mid 14's at best (at 2500' + DA)
295/45R17 Drag Radial's = high 13's, low 14's
Just Plasti-Dip'd the Chome 20's Black last night....looks way meaner now, but still not faster