The AUDI A6 (2004-09) 5DR AVANT 4.2 V8 QUATTRO S LINE TIP AUTO is a large premium estate, offering more luggage space than the A6 saloon and serving business users and families. In the UK used-car market, it competes with executive estates such as the BMW 5 Series Touring and Mercedes-Benz E-Class. Mycarcheck.com records 28 look-ups covering 14 distinct VINs, a modest sample rather than a broad reliability verdict. Checks show an average private-sale valuation of £1,400, average recorded mileage of 150,000 miles and about 5,000 miles driven annually. Cars had around 3.4 previous keepers, notably, across these checks. Its 4.2-litre V8, quattro four-wheel drive and automatic gearbox give the A6 Avant a rare mix of effortless pace, confident all-weather grip and practical carrying ability. It suits experienced drivers wanting a comfortable long-distance family or touring car, but expect fuel bills and upkeep to reflect its powerful, ageing luxury-car character.