The AUDI A6 (2004-09) 4DR SALOON 2.0 TDI 140 LIMITED EDITION MTRON AUTO is a large, four-door diesel saloon in the used executive-car market. It provides a spacious, comfortable alternative to mainstream family cars, while its automatic gearbox suits relaxed everyday driving. In the UK, it competes with the BMW 5 Series and Mercedes-Benz E-Class. mycarcheck.com records 390 look-ups covering 151 different VINs, giving a useful snapshot of cars checked rather than every A6 on the road. The average private-sale valuation is £1,500, and recorded mileage averages 138,000 miles; annual use averages 8,000 miles. Checks show nearly six previous keepers on average, so condition and service history deserve close attention. The 2.0-litre diesel suits commuters and families making journeys, while its cabin and settled ride reflect the A6's executive-car appeal. It is less suited to buyers seeking low-cost motoring: check the automatic transmission, maintenance record and wear carefully before purchase.