I have not seen the Hyde electric mount that some are using so I am not sure if it is practical to use with an outrunner....my motors have all be hard mounted to a firewall (rear mounted)
Without the gearbox to make noise the Plett's are about as close to silent as you can get

I dont really see any reason to make them quieter.....as for vibration, there is none that I can detect and on a RX battery consumption basis its 25% of what my glow engines were doing.
To me one bonus of the electrics is the cost savings of not needing a Hyde mount

Hopefully someone who is running one can chime in with some tangible benefits of using one on an electric motor.....