While I don't have the OEM XM radio, I do have XM in my car and I love it.

As to the supercharger, at least from what I remember, the supercharger rotors are now coated with a different material which allows it to work more efficiently and generate less heat as a byproduct - which in turn = more power. The openings have also been reshaped and the inlet and outlet flow improved.

I'll try to find some specific numbers for you later.