Yes, it's a safety item... if the rubber in the new mount deteriorates
and breaks, the engine is limited in travel. With the old mounts, if the
rubber separated, the engine was free to move/rock excessively under
torque load during acceleration; there apparently were incidents where
the engine shifted and jammed the throttle linkage at full open. The
downside, if I'm not mistaken, is that the new mounts may be larger and
thereby interfere with the fitting of ignition wire shields and the
normal routing of the spark plug wires.