Audi S5

Engine and gearbox are the S4's, and worth having for the same reason: a turbocharged petrol V6 and a conventional ZF 8HP that survives tuning software and shifts smoothly. What differs from the S4 is the bodywork, not the engineering.

There is an older 4.2 V8, naturally aspirated, from the previous generation. It is uncommon and should not be read as the same car with a bigger engine: different block, different servicing, different bill.

The quattro is permanent and mechanical, with a Torsen centre. The sport rear differential with active torque vectoring is an option many American cars carry -- it wants two different oils and is often neglected, because most owners do not know it is there.

Adaptive dampers are the norm on American cars. After a frontal impact they are replaced with genuine parts, at a price out of proportion to what the class suggests.

And the most commonly missed: behind the front bumper's side grilles sit extra radiators and ducting, because the turbocharged V6 and the ZF both run hot. They look like plastic, they cost like a component, and the yards do not have them.