I am an avid SiriusXM listener. The only time I listen to terrestrial radio is when I am driving through the car wash!
If you have a loved one with a Mercedes-Benz newer than 2003 it is very likely they have Sirius installed in their automobile. I think a subscription would be a great gift!
All you need is the ESN of the car to call Sirius and set it up. The ESN can be found under Radio < Sirius < Info or some similar combination of words. It is always in the Sirius screen < bottom left < bottom menu < number appears.
You can visit SiriusXM online to get more information or set up the service!