I have a 2008 BMW X3, which I am about to pick up from my dealer, after European Delivery. The vehicle has a navigation system. The price my dealer quoted to install a Sirius satellite radio was $960, not including the one-year subscription price. This is more than I care to afford. Can someone tell me if the vehicle is pre-wired for this unit? And, can an auto audio dealer use these connections? I am planning to have an after-market satellite radio installed, and would like to be able to run it through my present radio, rather than have a separate unit stuck to my dashboard or front windshield.