I've toyed with the idea, and even used some silicone material on the Y-motor. Leveraging advice from RobH2, I'd first try an alternative approach to setting the drive level for the stepper motors. You may find that the noise is mostly related to the motors currently being driven harder than they have to be. Under this approach, you decrease the stepper driver adjustment down to where the motor doesn't work, increase it back up to where it does, and then increase it a bit more for margin.

I recently did this and was absolutely amazed at how much quieter the printer is. See http://3dprintboard.com/showthread.p...ll=1#post40593 for some gcode that moves the X or Y axis back and forth while you futz with the adjustment. There's similar gcode for the Z axis and extruder motor near that post in the same thread.