I've got the single CD MB unit (2001) with the Bose upgrade. The power's OK and the quality acceptable, but the main problem is the lack of rear speakers. There seem to be only 4 speakers (of which 2 are in the door) so the sound is pretty two dimensional. The fader just lowers the volume as far as I can see. Is there any way of adding rear speakers - or am I just setting it up wrong.