Hey Jamie, I also have a BMW master tech friend (who got moved to Mini, almost against his will, because his customer satisfaction reports on those were the highest at his dealership). I've driven his 540, and it's a very nice car.
Anyhoo, I have a few friends en route to my place right now, and one of them is a total car nut. I asked him what he would do with 4k, '99 or newer, with BMW. He replied 328. I asked why. He said go with lower model numbers because there is less technology behind them, which are just more things that can fail. Iono, he's pretty big car nut, but everyone has their opinions. Just another thing to chew on.
He has a friend that has a 7 series bought on the cheap, less then 10k for sure, but not 4k. I'm pretty sure my friend coming over would strongly advise against a 7 series, due to maintenance costs. You can't assume that your 65 yo friend will do everything for free (or even cheap, it could still add up on a 7), and does he own the tools, and how much are the parts, etc. Good luck bro.
edit: just browsed for a bit, gotta run they're here already. Here's one
listing.
