[RMcNeal]

At a minimum, you'd have to replace both motors so they match. As I understand it, one has more torque for heavier slides compared to the other. The 300:1 or 500:1 is just a ratio, not necessarily how fast they run.
I had to replace one of mine recently as the wiring had pulled loose where the motor was improperly installed and allowed it to twist until it pulled out. Got a replacement motor on Amazon for $78.00. CW wanted nearly $300! The old one is still good, I just have to re-solder the connections on the circuit board on top of the motor when I get around to it.