XM is ultimately connected via USB, but via a serial to USB adapter. You will likely pay an arm and a leg if you even found an install shop to put it in (I highly doubt your dealership would put it in, and if so, be ready to pay huge money for labor). What city are you in? Your best bet is to try and find a guru on this board who's close to you and make a good deal with them to put it in for you.

