I've heard that they transfer a lot of vibration. I've also heard that it's better if you only run one. I can't remember which side though. 
Ill prob. only run one for now (pass side) only because thats the one that always breaks
Let me know how you like those motor mounts please. I've had a set sitting in my garage since last summer. I'm reluctant to run them because I think they will be too rough for my DD.
Ok but mine only get driven down the street, for the most part it rides on the trailer
