When you purchase a motor you generally use all the parts from the old motor in the new motor. In your situation you are also mixing parts from two different filters, XP1 (S) and XP3 (L). This might work fine or you or you could end up with water flow too strong for the tank.
Below is a list of parts that go in the motor:
Rotor Impeller (includes shaft and bearing)
Impeller Cover
Impeller Cover bearing