I was speaking with an installer at Circuit City about installing a Blaupunkt Munchen RDM169 head unit and CD changer in my Z3. He said that, although the Z3 is prewired for a CD changer, the prewired data cable would work only with a BMW factory head unit, not a Blaupunkt. Can anyone confirm whether or not this is true? I know that most BMW came with an Alpine head unit, but I heard that some factory head units were made by Blaupunkt.
