I have the Panasonic 8 disk changer for my 99 Passat. It works fine, and is controlled by my factory radio.
The only problem is that the radio only knows about disks 1-6. To play disks 7 and 8 you have to go to disk 6, then wait for it to finish, and it will move on to disk 7, then 8. You can skip tracks and fast forward to speed the process along.
Or you could not bother loading disks into slots 7 and 8.