ok, i got my 4.6 today, evrything is great except a few things. its an mkIII navigation, and there is no cd player in the front only a cassete player behind the sceeen. Is there anyway to put one in the front?? secondly, where can i get ahold of the operating system (mkIV) and lastly what do i need to install the satellite radio, just the sirius receiver?? would it be possible to put in xm instead?? thanks a ton!!!