I too have the safe and sound package with an RBZ radio, the documentation made it seem like it had Sirius, but once I got the car, to my surprise, it did not. My understanding is that it does not have the internals for Sirius.
My suggestion, which I intend to do once I have a bit of time is to buy the lockpick from coastaletech. From what I have read, it does a few things I like: It unlock DVD playing while driving, (why else would you want dvd player...) It enables the installation of a screen in the back, and also has RCA "in" cables, which would make a clean install of a Sirius adapter.
Please post if you find other alternatives!
