I missed out on a fairly good deal on a 330i after walking away (the dealer's admin fee doubled to $600 because I wasn't financing through them). Prior to that, I had BMW check it over themselves, and the car still had about nine months of factory warranty left on it. They found some minor quibbles, almost all of which would have been fixed under warranty.
Even though I walked away, I began wondering if it was possible to try to get BMW to CPO a car they didn't themselves sell me.
I know how exact BMW likes to be when CPO'ing a car, even down to the tire tread, so I'm sure there might be repairs and inspection and lots of money to do so, but would they even bother? If possible, how much would it cost? (I'm ignoring, for now, the obvious questions like "why did the original owner sell it to a 3rd party in the first place", "was it ever in an accident", etc).
I ask because there actually are a few dealerships around my area that have had customers trading in their BMWs... I'm guessing because of financial hardship or whatnot, so they trade down to a cheaper vehicle. I've seen a few good deals on what appear to be well-maintained 3s.