Do you have any idea how expensive such a job would be? I think I have the same issue on my m273 engine. There's a knocking sound at idle ( you can only hear it from outside the car though, if you get close to the engine bay) and the whole engine vibrates slightly ( I just replaced the engine and tranny mounts so the vibration isn't coming from there).
Also, how long do you think I can drive the car like this without major issues possibly occuring?