OEM would probably work, but looks like camera and switchbox are NLA??
BMW X Series (E53,E70,E71,E83) X3 3.0i Retrofit backup camera

but is available on Turner Motorsport
https://www.turnermotorsport.com/p-2...FQ-raQodOrwJqw

And this is an aftermarket alternative

BMW X3 E83 back up camera installed. - Bimmerfest - BMW Forums