Hi
Yeah, the Fireball 21 double would work fine. The general rule of thumb is to leave allow a difference in the numbers in order to avoid the ESC running on its limit, ie. 15 turn limit ESC = 17 turn motor, 11 turn limit ESC = 13 turn motor etc.
I think you will be happy with that combo for the moment, you will certainly notice an increase in performance over the standard 540 motor.
But believe me, you will soon get bitten by the NEED FOR SPEED!!!
