Costs & verdict
Everyday costs, plus how reliable and safe it is
In terms of purchase price, the S6 fits between the BMW 540i and the Mercedes-AMG E 53, while resale values for all three should be similarly strong. It's worth bearing in mind, though, that the regular A6 50 TDI does almost as much for a lot less money.
When it comes to fuel economy, Audi’s decision to go with diesel power gives its car an advantage over its petrol rivals: the S6 tops 35mpg in official tests, whereas its rivals return nearer 30mpg. What’s more, the difference is only likely to grow in the real world when you start putting your foot down.
Just bear in mind that if you’re lucky enough to be considering an S6 as a company car, it attracts a 4% diesel surcharge, so it still won’t be particularly cost effective on benefit-in-kind (BIK) tax.
Even the standard S6 is very well equipped, with 20in alloy wheels, privacy glass, keyless start, leather seats (heated in the front), and all those infotainment and visibility aids we’ve mentioned previously.
Upgrading to Vorsprung trim adds 21in alloys, keyless entry, heated rear seats, a panoramic sunroof, soft-close doors, adaptive cruise control and black ash interior wood trim, but it also carries a huge price premium, so we wouldn’t bother.
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