In addition to having a different suspension system compared to the 10, the 20 and 30 have different feet. With the latter tables, one can leave in place the rubber insert pads or remove them exposing the stainless steel balls inside. If one wishes to 'ground' the table to an isolation platform - such as the Symposium Ultra - one should remove the pads. If the table is resting on sensitive furniture, the pads would best be left in place. This choice could certainly have various effects including the amount and tightness of bass and perhaps the degree of detail and 'blackness' of background.
Different strokes.......