The AUDI A6 (2004-09) 5DR AVANT 2.7 TDI QUATTRO S LINE TIP AUTO is a large, premium diesel estate, offering more load space than the A6 saloon while retaining an executive feel. In the UK used-car market, it sits alongside estate versions of the BMW 5 Series and Mercedes-Benz E-Class, rather than hatchbacks or SUVs. Mycarcheck.com has recorded 267 checks covering 139 different VINs, a useful sample of interest in this older A6. Checks show an average private-sale valuation of £1,300 and average recorded mileage of 171,000 miles; the typical example has around five previous keepers and covers 10,000 miles a year. A history check is especially worthwhile. The 2.7-litre diesel, automatic gearbox and four-wheel drive suit long-distance commuting, trips and family holidays, while S line styling gives it a sportier edge. Compared with rivals, the Avant combines comfort, practicality and all-weather grip, but running costs and repairs deserve consideration for buyers.