Considering the whole rear subframe is mounted in rubber, it doesn't seem that far fetched. The rear diff bushings I have now are very close to being hard plastic yet did not translate to much of a difference in NVH in the cabin.

Winmutt, I had a different experience with the trans mount I got from you. I was having an issue with a gusset on the trans tailhousing bumping against the crossmember when I ran over speedbumps, etc... The poly filled mount fixed that right up. Other than that, I wouldn't be able to tell it was in there.