I only suggest it would be interesting to listen to Halcro's TT101 with vs without the rubber isolators (or whatever they may be made of). Of course, Halcro has to do the dirty work, so it is easy for me to suggest it from 10,000 miles away.
And the reason I bring it up is that Garrard guys remove the stock rubber surround between the 301 chassis and its plinth, whatever the plinth material. They say that the insertion of the rubber between the chassis and the plinth impedes the capacity of the plinth to soak up motor vibrations, and indeed it makes a lot of sense that that would be so. In a DD, any tendency for servo action to cause relative motion of the chassis vs the platter must be countered, so the same principle applies.
Gosh, the TT101 is quite smooth and quiet. Just looking at it in operation, it HAS to sound great. Love those coreless motors.