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The real wonder of this car will be its breadth of abilities. Unbelievable flexibility and effortless acceleration at all speeds with its monstrous torque output. Relatively good fuel-efficiency and quiet long-distance cruising, with the knowledge of the torque being there when you need it. So that'll make it a proper GT.

And, last but not least, four-wheel-drive quattro grip in bad weather, combined with a nimble, light-footed, mid-engined feel on twistier stuff - direct, sharp steering, clamped-to-the-road grip, easy oversteer on demand, supercar fun. Oh, and carbon-ceramic brakes to rein in all that speed.

The car will do 186mph, passing 62mph in only 4.2 seconds and 100mph in about 10 seconds. And it'll return up to 29mpg in normal driving.

The bigger picture is interesting. Why does this car exist? To be the ultimate Audi, probably - one that will be more expensive and more exclusive than any other R8, and built in smaller numbers. Given that the normally aspirated V10 from the S6 and Audi-owned Lamborghini Gallardo will soon be used to create the new RS8, probably running at around 480bhp and 430lb ft, this mighty diesel powerplant neatly takes the car in a new direction.

Importantly, it provides Audi a cool, high-tech marketing tool to attract those all-important US customers to the brand and, crucially, to a new type of fuel.

Diesel hasn't caught on in the States yet - but as fuel prices rise, no doubt it will. Audi will be right there, with a range of efficient, economical Bluetech diesels that will fly off the forecourts with a little help from this monster, linked as it is to the R10 racer hissing around the American Le Mans series and winning everything in sight. Or not winning...

Expect the TDI to be differentiated from 'normal' R8s in all sorts of ways other than its engine. Big duct on the roof, big engine ducting visible through the rear glass, different nose and tail and skirts like this concept, which has more intake area up front and different mesh, maybe different wheels and cabin. The ultimate Audi.

We'll have to wait for a drive in the production car to be sure, but I suspect Audi has created something special here. The diesel supercar has arrived, and it'll worry those old-school, high-revving, inefficient, noisy supercars out there.

"Something strange is working behind us." You're not wrong, Thomas. But it's something extraordinary, too.

Bill Thomas