shake, my imagination or

[chuckr]

hi, i'm somewhat new to MB diesels, i look at the engine while idling, and it is barely moving - sounds real smooth, lots of power, but in the car, idling, it feels like it's moving a lot, the idle is rock solid at 850 or 900 rpm...when i shut the engine off, it jerks like crazy. do i need engine mounts/shock? and is this a DYI proj? how long could i wait to do it?

thanks, Chuck