Faults:

Central locking failed at 41,000 miles (fixed under warranty)

Heated seats not working (fixed under warranty)

Battery failed at 48,000 miles.

Rear brake pipe failed 48,500 miles.

Brake down at 49,000 miles requiring new fuel injectors, spark plugs, thermostat, and ECU.

Temperature gauge failed at 50,000 miles.

Air conditioner developed intermittent fault at 50,000 miles, condenser fan replaced.

CV joints failed at 52,000 miles.

Audi Concert stereo developed intermittent fault at 55,000 miles.

Track-rod ends failed 59,000 miles.

The auto-box is becoming lazy and is sometimes reluctant to shift, sometimes delivering jerky changes.

General Comments:

The A6 is a joy to drive, and the 30-valve 2.8 litre V6 is a formidable power plant which packs a real punch, whilst also being very refined. Handling is as good as you would expect from this type of car; clearly delivering the levels of comfort expected in an executive cruiser requires some compromise in nimbleness, but the Audi doesn't spring any nasty surprises.

The cabin has a feel of quality about it, and the Bose sound system is considerably better than many people have in the homes. Overall it's a nice place to spend some time.

But (and it's a very big "but"), as you will note from the lengthy list of faults and failures, ownership has been a deeply painful experience. Ownership doesn't get much more expensive than this. Over the worst 6-month period, I picked up garage bills of about £2,500 exclusive of regular service costs.

Faults:

Volume knob on Audi Concert Stereo started to fail (jumped to max or min volume when adjusting). Apparently a common fault.

Air-flow meter failed, causing sluggish performance. Another common fault.

Rear wiper failed. Replaced by dealer.

Difficulty cold starting - probably glow-plugs starting to fail.

General Comments:

Overall, the car is pretty comfortable, with a reasonable amount of power from the 2.5 V6 TDI. Still runs very smoothly, despite mileage.

Sports suspension pack is best avoided - makes the ride too firm for comfort on poor road surfaces.

In hindsight, I think the 1.9 TDIs are a better buy. The 2.5 isn't that much quicker than the 1.9 130bhp, but is quite thirsty at 38 mpg. You can get nearly 50 mpg from the 1.9 models.

Overall, these cars are pretty good value, especially when they have high-mileage. It was much cheaper than the equivalent BMW 5 series or Merc E-class.

Faults:

Door locks failed.

Front electrical windows failed.

Front wheels squeal on turns.

Hesitates when accelerating.

Have had three instances of uncontrolled acceleration.

Computer display failed.

Front bumper pulled off on curb and tension ruined front fenders.

General Comments:

Car is a pleasure to drive when there are no problems.

Quattro performance is excellent in snow.

Numerous electrical problems have cast a shadow on my enjoyment of the car.

Acceleration problem represents a major safety issue that Audi is responsible for.

The car is not supported by the manufacturer.

Faults:

Transmission slipping after 100,000 miles. Numerous seal leaks for the same repair.

General Comments:

Love the car and hate the maintenance.

Faults:

Nothing in the six months of ownership - Can't comment on dealer service yet, as one isn't due until 60000 miles.

Only minor niggle is the driver info module/computer which can get fainter and fainter after long periods. Once 'cooled down' or rested for an hour or two, it is OK - until the next time.

General Comments:

A superb car in every respect. Eats motorways for breakfast.

Superb ride, leather seats and dual climate control. Understated luxury.

Very quick, and amazingly smooth. Tiptronic 5 speed works like a dream. Gearbox is altogether one of the best features on this car, as it adapts to the road conditions so quickly.

Not too bad MPG - but being heavy on the right foot is always tempting in a car such as this.