XM Satellite may be in bed with GM but Sirius has gone high-end with their partnerships. At least until 2012. Sirius has now extended its exclusive agreement to provide Mercedes-Benz with Sirius satellite radio as a standard feature, beginning with 2007 model year vehicles (coming out this year). Unfortunately, you’ll only be able to get the service with 2007 year SL-Class and CL-Class vehicles, and all AMG and 600 model vehicles at first.
https://gizmodo.com/gm-to-xm-hey-baby-want-to-come-over-to-my-place-133486
Mercedes-Benz also plans to extend the number of models with SIRIUS as a standard feature in the future. SIRIUS is available as either standard equipment or a factory option on Mercedes-Benz vehicles, with volumes expected at 250,000 vehicles over the next two years, a figure representing approximately 50% of Mercedes-Benz sales.
The subscription rate is bundled as part of the feature.
Prices for Sirius satellite radio receivers (no Benz attached)