Audi A6

The split on the C8 is by engine. The '45 TFSI' (2.0 TFSI, 248–261 hp) runs a 7-speed S-Tronic and Quattro Ultra, which drops the rear axle on the highway. The '55 TFSI' (3.0 TFSI V6, 335 hp) is the real Audi — the 8-speed classic ZF (Tiptronic) and permanent mechanical Quattro with a Torsen. In the stock the A6 is effectively all quattro; front-drive is barely seen.

Both engines carry a mild-hybrid system (48 V on the V6, 12 V on the 2.0) with a lithium-ion battery and a starter- generator. The big trap is the factory-defective Continental starter-generator (BAS) on the early C8 — it fails suddenly, the car cuts out while driving, and the fix here needs an expensive revised part.

The MMI Navigation Plus dual-screen arrives entirely on US software — budget for converting to European maps, even frequencies and the local language.