Any 7er is going to be a fair amount of maintenance work and money, regardless of year. It is likely the most maintenance-intensive of the BMW lineup, although a E38 is very likely less of a headache than the god-awful E65.

The E38 got a facelift in 1999 and received clear indicator lenses on sport models sometime soon after. The Steptronic was available on sport models only starting in 1999 or 2000, and I think became standard across the board for the last year in 2001. A 2001 E38 740i sport black/black looks absolutely gorgeous and is a brilliant drive. BMW has not made a 7er since the E38 that's as gorgeous nor entertaining a drive, so go for it if you are ready for the maintenance.