When using solid engine mounts, you have to have some give, as the car and the chassis flexes a little. I run a poly mount, they seem to hold up the best. As mentioned the rubber ones don't hold up well. And when I was young and dumb, I tried a solid rear mount, did not work out well, kept pulling the threads out of the tail housing where the mount bolted. I have even seen solid rear mounts break a tail housing.