Thanks for the update.
Which is the DSP amplifier? My system sort of looks like the following:
http://www.eurobuyers.com/instinstr/cdinstall.html
The DVD Nav is up on top.
The Silver unit below it is actually black in my car.
I have a sliver unit to the left of the first picture, rotated 90 degrees and flush with the rear of the trunk.
My Changer mounts as shown.
I do not have an optical cable anywhere in the car. Only the two regular plugs. Do you think I should go to the dealer and find out what's up? Maybe the techs who actually install the Changer at the dealer for $300 know why I don't need the hook up
But it is interesting that my changer connects w/o optical and yours requires optical. Without hearing what an optical connection sounds like in a 5 series w/DSP, I don't think I would be able to tell the difference, if any.
As for the Aux input, the instructions only say it will work with cars made from 09/02 on. Doesn't say anything about DSP
http://www.eurobuyers.com/instinstr/auxkitdir.pdf