I bought my LT1 three weeks ago and tried to get the dealer to install the XM system in my car. The manager told me that the vehicle would have to been "born" with the system already installed.

 

I was told by my dealership that they had problems with the electrical portion of the XM receiver system. If you have either the HHR with the 6 CD changer or if yours has the MP3 support then you will be ready for the receiver when the new model is released around Nov. or Dec. '06. Of course this is relying on an estimate from GM which I hope is accurate. Terk may come out with one before then, and if so it will probably be less expensive.