my friend has a 2002 infinity qx4 with factory navigation, and he wants to put in an aftermarket radio. the navigation unit and the radio arent all 1 piece. they are separate. he doesnt have a nav cd, so i dont know if the voice commands are played through the speakers or if the nav system has its own speaker. also the nav has its own cd slot for the nav disc. i dont think it can dbe done reasonably without it being a jerry rigged install. and there arent alot of qx4 forums out there. what do you guys think???