I have a limited not a srt just wanted to put in some more info.
The limited has a taller gear (3.27?) than the srt (3.06). The taller gear will also limit the top end of the limited.
I have a gps system in my car. At 140 mph the gps and speedo are only 1 mph off.
This obviously doesn't give you guys the info you are looking for but the more pieces to the puzzle the better.

I actually have no need to do 151 mph I wish I could get a 3.55 or so gear to help the 60 foot and 0-60 mph times.