Sinve the 99 A4 is prewired for a cd changer what exactly needs to be done in order to install one? Can I just go out and buy one and then just connect it. Or do I have to insert special parts and wires to the car. I don't really know anything about the sound system. Any advice on installing the cd changer would be helpfull. Thanks.... I was also wondering, I was told the a4 has eight speakers, I can only find 6. Does anyone know where all eight speakers are located?