The actual spec. on mount clearence is 13mm ..less is a collapsed mount.
It is wise to also change the rear mount, as a bad one changes the driveshaft angle and wears out the flex joint prematurely. Changing the front mounts w/o changing the rear trans mount actually increases that angle
b/c now the front of engine is back to proper spec , but the rear is not, so it is advisable to do all three at the same time...