1996 Japanese Z3.. need stereo wiring harness

[Coach Jess]

I am cross-posting this because the knowledge I'm looking for is probably known to an owner of a different model than mine.

I have a lovely red Z3 from Japan, the 15th Anniversary BMW Japan edition. I am trying to find the correct radio-side wiring harness to connect to the car-side harness receptacle, but the stereo system on the Anniversary edition was not found in any NA/EU Z3 models. I suspect it was repurposed from another BMW of similar vintage, so I'm hoping someone who has changed the radio on their 95-98 BMW will recognize the pattern, and I can buy the aftermarket radio-side wiring harness for that model and be good.

As a bonus, anyone who knows what the white, 10-pin receptacle is for would be welcome to share. It attaches to a thick cable similar to the antenna cable, fwiw.