Do the bolts holding them need to be set to a torque spec. R as tight as u want?
After markets are polyurathane filled.
by filled, I think you mean solid polyU.
Aftermarket mounts are usually available in a variety of hardness levels. Depending on your budget and your expectations, you may want to stick with something from hardrace or if you can accept a little vibration, then energy suspension inserts work quite well.