I just retrofitted a camera to my E90 and the online instructions will also work fine for the E70. I used my E70 to test things when I ran into roadblocks on the E90.
This one has been for sale for a while. Might be worth a call. Nobody wants a black car in FL.
https://jacksonville.craigslist.org/...780318862.html
I lived in CA a few years ago and east coast prices are a few grand cheaper. If you never have driven across country you must do it before the electric cars take over
.