Found a great site www.alldatadiy.com have tons of info.
To sum it up.
The becker head unit is connected to a left/right amp in the
left trunk (right next to the cd connector) I checked the connection
on the amp.. it is not standard.. (fader, and left/right input along
with speakers connections.) in short, pain in the butt.
The only way is to put in a new head unit and amp.. too much
work to ripe out part of the car. I just bought a factory changer
and hope it will last me a few yrs before I get the iche...