Peter, I love my car, and I say that having borne the high cost of operating her, yet at the same time there is NOTHING like driving a 7er. My Baby is a black/tan 1997 740iL (sort of).
In my opinion, do not buy an E38 without a warranty or else you will face some substantial expenditures keeping the car operating. Once you get used to driving a 7er, the desire to keep doing so, will compel you to accept maintainence costs that would not be tolerated with another vehicle.