Goose boy - we operate 27 AS350s with 2 axis autopilots, and that's what my chief engineer told me a couple of days ago.
TheFlyingSquirrel - as I understand it, the Squirrel was found to have numerous vibe problems. Some were removed/reduced by the antivibrator on the rotor head - some ground resonance (or something similar) difficulties were reduced by adding the springs on the back of the skids and dampers to the skid mountings. The anti vibration units under the floor are lumps of lead on flat springs and are mounted one under each pilot's seat. They are tuned in the factory to reduce the vibration levels felt by the front crew (engineers speak of 'nodes' whatever they are). It's probably the size and weight of the lead that makes them a problem if the spring or mounting fractures in flight!