Moin together

Moin V8 municipality,

I wanted to introduce myself briefly: name Jans and come from Northern Hesse: Fritzlar (near Kassel). For a few days I have owned a V8 Bj. 93 4.2 in silver (Condition: go so!). I drive him as two cars and I want to restore him pretty much "original".
I want to revive the BOSE plant and I have a question: the gamma cc Bose was a "supplement", I read that there is an address where these devices are checked and maintained? Since I want to connect a CD changer despite nostalgia, the question is whether there is another Audi radio e.g. Delta (22 cm?) (blue point, basic) what can the Bose system control and where you can connect a "ventilated changer"?
If no, where do I get the right changer with cable for the gamma? (Ebay has none!)

Oh, I'm looking for a cover (bose box) for the left door, too?

First of all Thank you and I look forward to your answers

Jan's Tschau