Joe, if your only going 4s why not stay with the MM and a Medusa 36-50-2200(or 3300). My 3905 was clocked by a bushnell radar gun at 42 mph through grass on 5s A123(nearly the same voltage as 4s lipo)and a 15t pinion with the 36-50-3300. I have not seen the motor over 120f and the ESC is hitting 98f w/fan. Looking at the specs for the 2200 I would guess you could get nearly the same performance as me with a 22-24t pinion on the stock spur. I'm just not sure if the 36-50 is a large enough motor to pull that tall a gear ratio. I also worry about running the 3300 at 46+k RPM but it runs very well for me so far.

Cant wait for my MMM, Neu 1512, FLM Hybrids, and misc other RCM goodies to arrive, spending my tax rebate on good stuff made in the USA! Hope I have enough left over for diffs, LOL budget e-maxx, at least that was my plan a few months back;)

BTW what heli you flying I have a whole pile of them, 4 ready to fly right now, 3 semi retired, and a couple more in boxes.