Does your check engine light come on at all? Mine did, off and on, sometimes it would stay on for a day or two, then go off for a day or two, light would say elevated emmissions. Found out it was the high pressure oil line for the vanos.$180 part, $2K in labor. I guess the cams in the V10 are responsible for a degree of rough idle.
Now I am trying to find out why one headlight like to do it's own thing, up and down, totally at random