Just because the stock 22's are 78 pounds and the stock Ram 20's are more (mine were 82 pounds with the 275/55/20s), doesn't mean they will be quicker in the 1/4 mile. The weights are close which is great that the 22's don't weigh any more then the 20's even less, but the majority of the weight is further away from the hub. Given 3 wheel/tire combos of equal weight and same overall tire diameter, the smallest rim will give the best times because the bulk of the weight is in the horizontal part of the rim.
Now consider that there are aftermarket 20's for $200 each that will drop amost 20 pounds off each corner, and the 17's and 18's are even less, and tighter to the hub. I bet there is more then .3 sec in the 1/4 mile by dropping the 22's in favor of rotary forged 18" Centerlines (something like 19 pounds per rim and under $200 each). I picked up .3 sec just by going form heavy factory 20's to heavy factory 17's on my Hemi, I can't wait to try some light weight 17's and good tires.