Initially there were only two engines available, though regardless of that you couldn’t call Audi A8 performance limited. Both 4.2-litre engines, with a choice of diesel or petrol, after the 2013 facelift the range jumped to six (seven if you count the S8) different units.

Diesel Engines

By far the most popular in the whole line up, with good reason, it’s the diesel engines that make the most sense. Currently the line up starts with the 254bhp 3.0-litre TDI with 580Nm of torque available from only 1,750rpm. That last number means it’s perfectly adept at completing overtaking manoeuvres and can sprint from 0-62mph in only 5.9 seconds. Opt for the long wheelbase model and that sprint takes a further two tenths of a second.

If you can accept a near 10mpg deficit then the 4.2-litre TDI completes the same benchmark in 4.7 seconds, faster than many smaller sportscars. It’s a great engine, with plenty of power and a suitably edgy engine note (when pushed hard, otherwise its near silent) but the biggest thorn in its side is the 3.0-litre.

For real world situations the smaller engine makes the most sense, and you’ll never feel short changed in terms of refinement or performance. The fact it’ll be cheaper to run is simply the icing on the cake.

Petrol Engines

In a car like this its strange to think there’s actually more petrol engines than diesel, though that’s due to the car’s popularity in the middle East, China and America. A 3.0-litre turbocharged unit kicks things off, with 306bhp while the 4.0-litre TFSI manages 429bhp and 600Nm. That’s enough to better the 4.2-litre TDI in the race from 0-62mph.

The other pair are at extremes to each other, with the 2.0-litre four-cylinder petrol being mated to an electric motor in the Hybrid model. It’ll reach 62mph in pure electric, but you’ll need the engine to allow you to hit the speed from rest in 7.7 seconds, and economy will surely suffer.

But if efficiency isn’t your game the W12 is worth a look; this 6.3-litre W12 can shut down half of its cylinders to save fuel. It’s never anything but near-silent, even under hard acceleration, and with 493bhp can complete the 0-62mph test in only 4.7 seconds.

The A8 is a great all-rounder – smooth and relaxed on the motorway but happy tackling tight corners or country lanes. This is helped by the excellent Audi Drive Select system which comes as standard. It allows the driver to fine-tune the throttle response, steering assistance, gearshift points and air suspension settings across pre-set levels – comfort, automatic and dynamic.

There’s a noticeable difference between the three, but the automatic setting is so capable, it tends to be most drivers’ default choice. All models, with the exception of the 2.0-litre TFSI Hybrid come with the renowned quattro four-wheel-drive system as standard. This means extra reassurance and grip when accelerating hard, or when cornering in wet or slippery conditions.

The air suspension guarantees a superbly forgiving ride and the A8 is incredibly stable and reassuring at high speeds, though the new Mercedes S Class is slightly more comfortable. We’d like more feel from the steering too; it’s responsive and direct, but feels artificial and when driving quickly there’s no hiding the A8’s considerable weight.