One of my complaints about this design is that I did not have a place to mount my XM reciever...that is before i mounted the reciever right on top of those holders. Now before anyone is quick to judge take note of this:
(a) I dont care what the Germans had in mind for their design. I bought this car in America (i.e. the steering wheel is on the opposite side). If Germans dont want Americans driving their car, then they can stop selling it in America.
(b) A big part of my driving experience is music. Nothing gets me more fired up at 5:45 am than listening to ACDC with the top down (okay that is a bit extreme, and fabricated

)
But I know the idea of some XM receiver unit on top of a factory CD shelf sounds appauling. But honestly, you cant tell it is there. You can check a previous thread and look where dcallas mounted his reciever.
XM thread
The place I mounter my reciever is working out great. It is low profile and you cannot tell what is behind it. Plus, when I sell the car, I can just take the velcro adhisive off and hopefully it will still work and look like new!