Excuse me if this topic has already been posted, I was too lazy to search. I was on the Tesla site just now, speccing out a Model S for price comparison, and in the radio section I noticed that it says the glass panoramic roof is REQUIRED for XM satellite radio. Why? My 2011 Challenger R/T has no such requirement, it has a metal roof and Sirius satellite radio. And that's another thing --- Is the satellite radio in Teslas XM or Sirius or both? Didn't they merge? I'm just used to specifying Sirius because my R/T has that. I want to be able to listen to Howard Stern and 80s music and comedy channels when I get my Model 3, but if it is going to cost tons more money for options I don't even want, nah. Skip it. I REFUSE to get a glass roof, I just plain don't need it or want the sun hitting me through it, (I like my R/T dark and cool inside with the A/C on) and I don't want to pay $1000+ for a stereo that has satellite radio in it.