I run the 1.5d geared 22/58 (3905 tranny) on my erevo, with a pair of 4s lipo's at the track all day w/o issues, max speed is 50mph and is PERFECT for racing.. I can show up just about anyone I've come by.. drop in a 5s or 6s and with the same gearing I can easily get to 62mph with a long run way I'm sure I could get 65mph on the 6s. Change up gearing and 70mph is possible. I run the MMM w/ the Neu 1515 1.5d and again it is perfect iMO.
Here is a youtube of just some onroad runs to give you an idea... sorry not track video yet.. but I've run about 10x now approx 1-2hour sessions ea visit w/o problems..
http://www.youtube.com/watch?v=85v85Pn3DMk
