HIGH speed, long distance cruising is what big German cars do best. Bred for the Autobahn, these luxury limos lap up the miles with a seemingly endless appetite.
But that zest for speed has always had a sting in the tail - fuel consumption. Big cars mean big engines and that means a big thirst.
Only recently has diesel technology been able to deliver the goods in terms of performance for such beasts and Audi has come up with a stupendous offering.
Using a three-litre V6 engine in its sumptuous A8 saloon, Audi has created a car with the best power to weight ratio of any mainstream production diesel.
In its class it can outperform anything BMW or Mercedes has to offer at a similar price. In fact the diesel which the Audi uses is so potent it can even outstrip the petrol powered three-litre V6 A8.
On paper the A8 3.0 TDi Quattro has a reported top speed of 150mph and a 0 to 62 acceleration time of 7.8 seconds - which for a diesel in a car of this size is phenomenal.
While it is lapping up the miles, the A8 is also capable of averaging a claimed 32.8mpg - a figure I found to be quite conservative on a long haul where in excess of 36 to the gallon was more realistic.
Quite simply you would not know this was a diesel with the exception of the reluctance of the fuel gauge to move.
Superb sound insulation keeps the interior as serene as a car in this league should be - and the whole vehicle is beautifully appointed.
Audis have never been as ostentatious as BMWs or Mercedes. Instead they have qualities all of their own which in many respects makes them more satisfying.
Despite a plethora of additional equipment on this particular car which pushed the price up from £47,380 to £55,610 it remained a driver's machine and not a high tech workstation.
For example, the multi-function control unit which operates most of the vehicle's features - audio, ventilation etc - is much more user friendly than the BMW I-Drive system and there are a cluster of controls mounted on and around the steering wheel but they are all logically placed and easy to use.
The list of extras that pushed up the price of this A8 by almost £10,000 included onboard television, xenon headlamps that look round corners, keyless entry system and a BOSE sound system.
The result of the extras was a car that lacked nothing - even the boot opened and closed automatically - and at night as you unlocked the car additional lights illuminated the door handles and ground around the vehicle in a blue-white glow.
Classy is not the word. Every aspect of this car has quality stamped all over it. But the acid test is how it performs and how you and your passengers feel after a long journey.
With the A8 the answer is always going to be one of absolute satisfaction. As they say, you get what you pay for - and for £55,000 you get an awful lot with this car.
FAST FACTS
Audi A8 3.0 TDi Quattro
Price: £47,380
Mechanical: 233bhp, 2,967cc, 6cyl diesel engine driving all four wheels via 6spd automatic gearbox
Max speed: 150mph
0-62mph: 7.8 secs
Combined mpg: 32.8
Insurance group: 17
CO2 emissions: 231g/km
BiK rating: 32%
Warranty: 3yrs/ 60,000 miles; 12yrs anti-rust, 3yrs paint