As far as 140 cars goes the S320 is probably the best s-class to get from a repair bill point of view. Sounds like a cream puff and it's got very good mileage. The engine is very reliable, pretty much trouble free. I don't know if MB got the wiring harnesses fixed by 97 or not but I would definately check out the insulation on the wires on the engine wiring harness and make sure it's not flaking off. Take a close look at the cam cover seals and make sure they are not leaking(no big deal if they are, but if so you might get a free repair before you buy the car) Other than that make sure the services have been performed in the maintainance book and your good to go.