If you are talking a factory OEM BMW stereo:
You might be able to wire it in, but only if you know which BMW deck you have and/or what company BMW used to make the stereo. So you can know what types of harness to adapt to in the back. I know in the past they used a company called Blaupunkt, but they also use Boston Acoustic, and Bose stuff. It will be a rough game to try that install.
If you are talking about just the changer, then I have no freaking idea what type of plug or adapting that is going to be. And frankly I don't think that would work.
My only ideas for you are to check with
Scosche 's website and see what type of converting or adapting you can do. and know that the harness you need for your current plug is:
This oneBut honestly Wolfen6137, you would save yourself a world of painful installing and adapting, to just buy something that you know works. If I was you I would only install a name brand deck, if this is BMW OEM business. Not worth the time. But good luck whatever you decide.