I've got this all done, so here is how it breaks down
ANY composite video input can be displayed via your idrive using a new unlocked menu
You'll need a few of these part #61131383776
Add $601 to your VO in CAS+NFRM
Code CIC
TVM_VARIANTEN
vm_l4_most_fkat
Change TV = wert_21
Use the part number I gave and add one to both the yellow composite (video) ground and +
Pop your CIC out and place the two new pins in bottom row of quad connector. + goes to 18 and - goes to 27
Will post a nice clear DIY if Amazon ever gets their shit together and delivers my mini pc to the right house.
I also have my OBD cable routed behind the cover, so you don't see shit, it starts up and turns off with the car so gauges from MHD available thru a couple limp wristed spins of controller