Works great in coach as much better than small speakers in ceiling! Portable as well for outside picnic table, beach etc. Also have Bluetooth sound bar in coach if I don't want to use battery Bose but it puts out way more sound than needed!!
In my georgetown I just ran the puck up the side moulding and put it the overhead cabinet with a bracket on the inside roof. Be careful to stay away from metal frame, the fiberglass has no effect on antenna. Three years now and no problems.
It is attached to the inside of the cabinet. I made a bracket that screwed to the top inside of the cabinet and placed the magnet base on the bracket. It is inside not outside. The fiberglass does not bother the reception, but you must watch out for metal frame in the roof. Hope that helps.