I think that i will try my Neu 1512, 3300Kv on 3s and see the performance and run time. i have an eagle tree so i will be able to monitor the amps drawn by the motor, and if it pull too much amps and the run time is too short for my taste, i will order a 4s pack.

I have my 1509 2700Kv on 3s in my slash and this little motor put alot of power in the slash and i think that the crt.5 is about the same weight than a slash.
My slash is 6.1lbs now, with the FLM tranny case, Koolflight UBEC, badlands tires and LX one shock.