Today I've replaced one of the motors. It works fine, but the metalic cylinder is just bit bended, as well as the propeller adapter.
It can be perfectly used to fly, but not for recording good video, because this is a source of vibrations, even if you have a vibration isolation mounting. At the end every little factor is going to affect the video results.
The motor comes with everything you need to completely replace the old one: motor, screws, motor holder and the propeller adapter.
If you don't connect the wires correctly with the ESC (not colored wires), you'll notice it because the motor will rotate in the oposite direction. You just have to swap two of them in order to correct it.