Audi S7

The reason to import one is the engine. In Europe the group launched the S7 with a diesel V6 for emissions; in America it stayed petrol. So this is not a cheaper way to buy the same car -- it is the only way to buy a different one.

The gearbox is the conventional eight-speed ZF rather than an S-tronic, and that is precisely where it differs from the lesser A7s. It takes serious tuning software, shifts smoothly, and carries none of a dual-clutch's temper.

The engine wants uncompromising servicing on both generations for the same reason: the turbochargers sit in the vee of the block, in the hottest place and the hardest to reach. Thin servicing kills them first, and replacing them is neither quick nor cheap.

Suspension on American cars is adaptive air. A bag, a sensor or the compressor damaged in the impact costs a serious sum to put right -- and it is the expense that most often surprises, because auction photographs do not show whether the system is intact.

The nose is specific and expensive. Behind the bumper's side grilles sit extra radiators and intercoolers for the twin-turbo engine, and the front brakes are 400 mm. Those parts are not in the yards here and are bought new. Plus the sport rear differential, which nearly every American car carries and which wants two different oils every 60,000 km, not one.