I woulod avoid the 2002 to 2004 E65's...
As much as I love them, up to 2004 the E65 had oodles of electronic gremlins and the car was not completly debugged yet. Also there are very few people that can actually work on that car, so expect your back yard mechanic to break it more then he fixes it.
As for the suspension error, you will have to put that car on diagnostics to further figure it out, there could be a ton of things.
If you like the E65, I did a lot of research on it at the time, and the most reliable is the 730d from 2004 onwards, and I will start looking there. Perhaps a bit more money, but if you wait some more the prices will come down.
140k is a good price, but if you are going to be using BMW to do the repairs, that car is going to cost you.
Also, its not a E46 where you can pick up interior/body parts at every scrap yard, spares are expensive.
I dont want to put you off the E65 cause they are purely awesome motor vehicles, and I would buy another in a heartbeat... just maybe avoid that 02' 745