I have a BMW trunk mounted 6 Disc CD Changer made by PIONEER that I had in my 92 750il. It fits the following BMW's: E-36 3 series, E-34 5 series, E-38 7 series (without DSP/premium sound system), E-32 7 series, E-31 8 series.
It is about 3 years old and plays perfectly.It comes with a mounting bracked and is about an 8 out of 10 cosmetically. The model number is CDX-M91zbm. BMW sell this unit new for U$ 727 plus $23 for the install brackets.
(it is on page 11, item C in the 99 Original BMW Accessories Catalog). I sold the car without the changer.
Price: $325 shipped anywhere in the US.
Please email me at [email protected]