If not flo-flex do replacements, made from poly urethane... The way they are designed they cannot break as they have a seperate bolt right through them, with isolating washers either side.
Ive run them for over 5years and 60,000miles from using the car as a daily, thru several track days and now 5-6k with the turbo engine in, not a single issue. No vibrations and yet the engine is unmovable in the bay, you can feel the car move when you touch the throttle rather than the engine rocking on the mounts.