I am in the process of doing the same thing. You are right in the fact that you will need all new electronics rx,servos,esc. If you keep the same motor make sure you get a esc for a brushed motor, which I beleive the Cub has. I am changing the motor also to a brushless (mor Power). I am having trouble figuring out how to mount the motor. Also I cant fine where the CG is on the plane (not written anywhere that I can find). My cub is on floats. Two sucessful flights and one not so successful put it into a stall (SPLASH). Good time to change over, nothing works.