Another gearing ?
 

E-revo mmm 1515 2.5d 6s mod1 gearing 40/13 spur / pinion gearing would this set-up be alright. Mostly bashing.

Using the calculator (http://www.scriptasylum.com/rc_speed/_top_speed.html) it looks like you should be geared for high 30's mph, which I think is a good place to start. Once you see how it goes and what temps are like, if you want more top end I'm sure that setup will take up to a few more teeth on the pinion without too much trouble.
I haven't looked at the E-revo's much, will the be enough room between the motor and transmission with gears that small?

Diff set up of 54/15 32 pitch gears would this be better for a 1650 or a 2200 mmm 6s set up.Maybe a few more teeth on pinion.