That's really interesting, but I'm curious to know if that amount of vibration is expected. It seems like something isn't mounted correctly from the videos.

Yes, that level of vibration is not normal, and is due to the fuel injection pump being out of adjustment. Because the fuel regulation is mechanical, it is possible to develop this sort of resonance. If you google for "OM617 rack dampener bolt", you'll find lots of forum hits about it. This video was taken before I was aware of the cause.