here is the SiriusXM link to the devices used in BMW vehicles:
http://www.siriusxm.com/help/findsirius#BMWGroup
The complicated "technical" information per advanced research and SiriusXM in-house experts is this: "CIC/HighCIC Mid" units are high fidelity and are effectively a circuit board within BMW's own navigation head unit (and share the XM technology). "Champ2+" is a standalone Sirius receiver with subpar sound quality. The numerical difference in decoded sound between the two devices is 128-320 kb per second (in CIC) vs 32-64 kb per second (in Champ2+), thus it can be four times worse in the standalone version. To get the "better sound" one must order not just the Premium Package and Premium Sound Package - 16 Harman Kardon speakers, bla bla bla (which I ordered both for my brand new 428i), but also the Navigation Option or Technology Package (which I didn't order as it was never explained on the website or by the dealer that those options would anyhow affect the sound quality of the satellite radio (
http://www.bmwusa.com/Standard/Content/Owner/iDrive/Overview/AdvantagesofOnBoardNav.aspx).
I work in the music industry, and as crazy as it may sound - SiriusXM and its sound quality in the car is equally important to me as the car's performance itself. I feel cheated and pranked - like installing a Chevy Cruz engine into a Lamborghini body and selling it at a full Lamborghini price. I can't believe they even install that crap into a brand new 428! The delivered car has another another physical issue, so right now I'm working with the dealership to figure out the solutions. Big issue: the navigation or technology package are factory-installed, SO there's not much that can be done after-market to fix the issue...
If you care about the sound quality of your BMW's satellite radio - read the above carefully and think twice before foregoing that $2-3K upgrade option which is logically unrelated to the sound. I would've definitely paid the extra money and the dealer would've made the extra commission.
BMW should make this issue public, visible, and educate the salesmen to educate the buyers about something that matters a lot, if even to a small group of people. Buying a premium brand - I expect to have all information disclosed, and that "small" issue is not small to me (and to thousands of other current and potential owners and everyone on this page).