I just bought a 2007 E63. What a car!!!! However I have noticed that when stopped or at slower speeds I hear a "clicking" sound coming from what seems to be the right rear of the car. It doesn't do it all the time and the intervals between "clicks" changes. It might do it at higher speeds as well but with so much other noise I don't notice it. Does anyone know what it is?

Check that. I listened again and it is more of a muffled knocking sound.

Maybe the fuel pump..?