Mine does not have XM, what I did was take a FM modulator and the buy an rca to headphone jack and plug my ipod in that way, below are the two i used.
You have to buy an adaptor to connect the antenna from the modulator to the one in our car as they are different. Sound is great, it was cheap and clean install.
Amazon.com: Movies 2 Go FM100A FM Modulator with... Amazon.com: PH62089 Stereo Mini-Male to 2...