I have a MCS on order with delivery in late April or early May. I have ordered the Navigation system as I have had them in previous BMW’s and enjoy playing with them. My question: is the AM-FM radio reception compromised due to the fact that the MC with Nav uses only the small shark fin antenna for both the Nav and radio? I live in a rural part of Southern California and radio reception is an on going problem.

I don't think the shark fin antenna is used for the AM/FM reception. There is an antenna that is in the passenger side back window. Kind of like the ones in some american made cars that has a thin wire attached to the glass.

That's right and I have never had trouble with it. AM works like a charm..