Searched some and didn't find a definite answer to my question. I've heard the actual antenna sticking out from the roof is the AM antenna and there is another FM antenna built into the rear defroster? Is this true? I would like to remove the roof antenna to make room for a CB antenna on my girlfriends '04 mini cooper. Thanks for the help!

 

Not sure exactly when they added the diversity antenna to the rear glass, but I read that it was in 2005, so you might not have one there and may only have the roof antenna for FM. I would unscrew the antenna mast and drive around to see if the signal / reception degrades, and if not, you're good to go. Otherwise, you might choose to add one of the aftermarket windshield antennas (not sure if they still have these around?) or hidden antennas for your FM reception. Be aware that the aftermarket antennas probably will not be as good as your OEM roof mast antenna in terms of reception.