i read in the manual that there is a hook up for sirius sat. radio. and that's what that button is for. So that would mean that the factory radio is satellite ready. right? well does anyone know if you can hook XM sat. radio to it instead? i already have the xm, and it should hook up right?

in theory, yes, but they may have some sort of coding so that it will only work with sirius..

In order to use satellite radio you still need the tuner for whatever company you will be using, XM or Sirius. I believe they both are compatible. Or, you you could just get the XM Roady2 like I did, and not have to worry about disassemblying the dash to install it.