THE initials VW conjure up a certain image.

But let's think of them separately.

The V formation is undoubtedly the most effective engine design, says the German car maker. That's the reason it powers the world's finest limousines.

But due to the length of the cylinder, it also takes up a sizeable space, limiting its use to only the largest cars.

Now for W. Not so much Double U as Double V. The W shape puts eight cylinders in a W formation that manages to be small, compact and light. Result: Tremendous performance from compact dimension.

That's as far as this lecture goes. I've never believed that a motorist should need to understand the technology of what happens under the bonnet, and that photo above of what the W8 engine looks like means little to any of us.

But this 4.0-litre engine, generating 275bhp, is at the heart of a car that's built for speed: standstill to 62mpg takes just 6.5 seconds, and the car will race on to a top speed of 155mph (please, no angry letters about safety and speed. I'm just reporting what the car is about).

VW acknowledges that control and safety are paramount, so the W8 is also equipped with four-wheel drive (VW call their system 4Motion) for "the ultimate roadholding experience". You can choose it with either a six-speed manual gearbox or a five-speed automatic.

Let's just accept that VW has achieved that aim of "tremendous performance." There's no doubt in my mind: this is a wondercar. Smooth, quiet, elegant; a subtle interior with a welter of sophisticated equipment.

But most of all, an ever-ready store of near-silent power which whooshes the occupants away with magical acceleration.

And in this car we have the added benefit of four-wheel drive, or 4Motion as VW like to call it (just as sister company Audi use the name quattro).

Indeed, it's Audi which you expect to produce such silently powerful mini-limos for captains of industry.

VW's mid-range Passat is now taken to extremes with this concept of W power.

It's rather like taking a regular Ford Mondeo and fitting it with a huge Jaguar engine. It is ironic that Jaguar, which set out to bring lord-of-the-manor walnut-and-leather opulence to lesser mortals, has just given its baby X-Type a small (2.0-litre) engine and put it on sale at under £20,000. So VW has taken its repmobile, which usually makes do with a 1.8 or 2.0-litre engine, and doubled its size an engine that's not only twice as big, but has the extra bonus of this W formation.

The cabin is also more spacious than you'd expect, and VW has taken up a little of Jaguar's styling by splashing a modest amount of polished walnut around the cabin.

But mainly it uses the restrained styling of German functionality smart Nappa leather (black in my test car) and simple aluminium rings around the dials, with more chrome highlights outside, framing the windows and on the twin tailpipes.

Light alloy wheels (17 inch) help appearance and boost performance. Roadholding and traction are also aided by low-profile tyres.

Bi-Xenon headlights provide a powerful high beam for improved night visibility.

The combination of limousine comfort and sporty performance is extended with the addition of practicality from an estate version.

Bottom line: this is a lovely car from a fastidious maker, but intended for a select few. Fuel consumption can be as low as 15mpg, which is lower than the insurance rating 18.