When mine let go there was no danger of the prop suddenly flailing around - the rubber contains metal mouldings that kind of interlink with each other so, despite the donut being in pieces, they remained connected together - so much so, that I drove it 70 miles home!





One of the problems with the aluminium discs that contain the rubber bushes is that the ones I've seen didn't have a centre bush to locate the prop and the output shaft, but that shouldn't be hard to add.



I can't say I've noticed any extra vibration with my adapter, but it was professionally machined to be balanced from the outset.