I also hate the shiny cheap plastic 20" covers on the R/T. From what I understand though, the gear ratio is only different on the manuals. I believe the gear ratio is the same for the automatics for both the 18 and 20. I do prefer the 20" wheels though because it fills in the wheel well a lot better. I will likely get the 18"'s and replace with aftermarket replica srt aluminum rims, or just wait for the SRT rims to show up on ebay. If you order the rims from dodge, they are almost $900 each (from what I understand).