From what I've read, it appears that the USASpec adapter will use the Ext CD Changer controls for the iPod, and the DVD controls for the AUX. Therefore, it should not interfere with XM. However, you cannot have a add-on CD Changer installed (like I have).
It looks like it will be the ideal adapter for a stock H2.
I can't believe how many adapters are coming out for the iPod. I own an Onkyo home stereo, and Onkyo sent me an email that they will have an adapter available in June that will let the receiver control the iPod via remote.
