does anyone know if 04 ZO6 came with theCD changer opition? or how to tell if the aux on the head unit has the ability to control another divice. I have read that some do and some do not, units look the same front and rear, both have the 9 pin plug in the back and the aux button on the front. I want to add a media controller, XM, 12 disc changer, amps.... and keep the oe unit easy to work. thankful for any and all input