Joe,
  I run the Neu as well and use the Hyde mount with it.  After about 30-40 flights, I'll start hearing a vibration that wasn't there before.  I have found that it simply comes from the rear mount not being tight enough.  (What that amount is, I can't answer)  My solution is to wrap electrical tape around just the part of the motor that touches the mount and the vibration disappears.  I don't know if this is suitable for your application but maybe it'll give you a clue.  If there is any sloppiness, you will certainly get that vibration with this motor. 

I agree with Arch, after about 75 flights, take the gearbox off and grease the gears.  It's very simple and F3A Unlimited just came out with some grease for these motors that is inexpensive. <br type="_moz"/>