Everything wears out eventually

I have seen mounts drilled and sleeved, and then bolted together for a semi-solid mount. Seemed decent enough.

If you still have rubber subframe bushings, and rubber trans mount, vibration would be minimal, I would think.

I was under the impression that poly, while less deflective or susceptible to oil, shears over time, and so does not last as long as rubber. I could be wrong.

The only place I know of that would have them if they were available is energysuspension. They dont appear to list any