talked to 2 different service centers and both say that if a car was not configured with premium audio there is no way to "upgrade" to satellite radio at least at this time.... Unless someone else has heard differently... Otherwise would be on a lane to Indiana right now!!!!
You put Satelite radio on your phone and you play satelite radio using bluetooth. I have been listening to Stern in both my Model S's since 2013 and it works great...no need for the premium upgrade for 2k.
Not sure what the annual fee is for Satelite mobile but i can assure you it is way less than the premium upgrade pkg