I checked and all of our MOT-24500X2500 and MOT-24500X2500B 24 Volt 500 Watt motors have the same terminals as the Razor E300s original motor, so they would be plug-and-play with the original controller with the addition of a CNX-W6.3FH-2T connector housing.
Our 24 Volt 500 Watt motors will work with the original controller and throttle. Since the controller is rated for 30 Amps then a 30 Amp breaker or fuse could be used as long as all of the wiring is 14 gauge or thicker which I believe that it is.
Jon gordon