M100 does it need a diode?
Whether a motor needs a diode or not depends mostly on the ESC that is used. Many ESCs have the diode built in already. Some come with a separate diode for you to put on the motor. Sometimes larger high amp motors may need a diode because it would be too big to fit on the ESC. Odds are a tiny motor like your M100 doesn't need a diode, but you should consult the ESC instrucions in this regard.