I have the HDX300 motor and it works fine. The can of the motor does spin, so make sure you have your wires tucked well.

It will run the heli fine with plasti-blades and the DD tail. The Sonix 18A or any 18A esc for that matter will be plenty. You will probably like the headspeed of a 9t pinion.

For some reason, I can't get better than 75 mah/minute with my set up. Many people who have the E-flite park 370 and E-flite esc seem to report better mah/minute efficiency.