Does anyone know if the OEM Alpine head unit in a 2004 XKR is compatible with the AI bus that orher Alpine audio systems use. I am going to remove the Nav system display and switches, cut a hole around all that stuff and use a new mounting plate that will house a Garmin NUVI 1450 along with a Sirius Sportster 5 reciever. Additionally I will be replacing the Alpine head unit with either a current Alpine or JVC head. I would like it to play nicely with the Alpine CD changer and the steering wheel control.