The changer you want is an Alpine S634. You will also need a Soundgate or Peripheral adapter, but check with them that their adapters work with a 2003 w/Nav.
However, you will not get track names on the screen. The only way you might be able to is if you hack the car's IBus, and to find out how to do that, you'll have to ask someone on the HacktheIBus group on Yahoo (groups.yahoo.com).
However, you will not get track names on the screen. The only way you might be able to is if you hack the car's IBus, and to find out how to do that, you'll have to ask someone on the HacktheIBus group on Yahoo (groups.yahoo.com).