Hi Jim,

Well, first up, the new 3 Series in 320d format actually does have a new engine; the power and torque figures may be the same, but a new injection system and an additional turbocharger have been added to make it cleaner on the emissions front. Obviously, the Three is a smaller car than either the A6 or the 520d, and – if it were our money – of these three we’d be going for the 5 Series. It’s just such an accomplished car in all departments, while the A6 (as lovely as it is) still has some Audi foibles like an occasionally unsettled ride and inert handling. That 204hp diesel engine in the A6, though, is a peach. You can’t go wrong with any of these, is the catch-all answer.