My 1998 C280 is showing these same symptoms; vibrating in drive while stopped. It does get better once the car warms up a bit?

I asked the local MB shop for a quote to replace the mounts. They said approx $100 each for L and R mount, $30 for tran mount and $400 in labor! I asked why so much in labor, and they said its because the engine, tran and rear axle has to be aligned very carefully? Not sure what they are aligning? Are there shims or something?

I am quite good with mechanical stuff, and thought I'd try it my self. Does anyone have any advice on replacing these? It does look tight with the V6 taking up most of the compartment. Is there a good manual for this car?

Thanks for any Info.