Are 1997-98 Audi A8 Quattro's good for 200k plus?

Are older Audi A8’s (1997, 98, 99) a worthwhile way to get a luxury automobile at reasonable price with AWD, decent Hwy mileage and a lifespan up to and over 200k mi

Maintenance/repair costs on this vehicle are EXTREMELY high. There is nothing whatsoever economical about the Audi A8. It may go 200K miles, but you will spend a boat load of money to get there.

Well, “EXTREMELY high” is a relative term. The audi will be more expensive to maintain than a ford/honda/toyota/gm, but not as expensive as some other luxury cars. If you are really in the market for a “luxury car” that’s just part of the cost. As usual, there is a trade-off between purchase price and maintenance cost, the cheapest car may not be the best value. Look around to get a realistic idea of what condition/mileage car you can get for your budget. When you find a promising car, take it to a good audi shop for a pre-purchase inspection (expect to spend $100+ for the inspection). Use the information from the inspection to decide and negotiate a better price. These cars can be maintenance hogs compared to ricers, so don’t be shocked is you end up spending at least several $100 per year on routine stuff. If cost is your primary concern, you probably want to look at something else. If you really want a luxury car, the maintenance costs should not be out of line with a bmw or a benz, maybe a little lower.

When (not if) the transmission or major driveline component fails, the car is effectively totaled.

If they have been given good care, then they may fit your stated requirements. If not they could turn very expensive very quickly. For example something as simple as replacing one tyre when the rest were well worn, can cause serious expensive damage in those cars. It would be difficult for you to tell.