I was looking into this for my E36. I believe you can use your stock deck with the Dice unit. You need the CD43 unit if you want the song info to the displayed on your radio. As for connections, europeanautosource provides wires that connect in trunk that you run back into your car. Or wires that connect from back of radio that you run to the glove compartment. In both cases you lose function of your CD changer.