This comes as a surprise. Volkswagen expends a lot of effort claiming to be an environmentally-friendly manufacturer, and extolling the virtues of its ever-increasing range of low-CO2 BlueMotion models. Yet consider the Touareg R50, a car which must irritate London's ex-Mayor Ken Livingstone like a wasp in the underpants. Ken's only consolation must be that Volkswagen is building a lot more BlueMotions than R50s.The R50 takes as its starting point the five-litre V10 turbo diesel Touareg, and then goes right over the top. In other Touaregs, the V10 produces an already sturdy maximum of 309bhp, but here it has been uprated to 346bhp (available, incidentally, at slightly fewer revs than the standard engine's peak).The result is a mild increase in maximum speed and a 0.7-second reduction in the 0-62mph time to 6.7 seconds, which puts the R50 in the same ballpark as the Golf R32. For the not-quite-£4000 you pay over and above the price of a V10 Altitude TDI, you also get various body styling tweaks, 21" ten-spoke alloy wheels and sports suspension which reduces the ride height by 20mm.This does not make the R50 quite as much of a tarmac terrorist as you might imagine. It's certainly quick, but to get the best of the performance you have to opt for manual control of the standard six-speed Tiptronic automatic. If you don't, the R50 can feel slightly sluggish - which, considering its very considerable bulk, is none too surprising.Equally understandably, it's not especially nimble through the bends, and realistically it never could have been. When you present the blokes in your suspension department with a tall, heavy, powerful car like this, they have to devote a large part of their cunning to making sure the thing stays on the road at all. The R50 may be nearly as quick in a straight line as the most powerful Golf, but it couldn't possibly be made to keep up with it through the corners.Fair's fair, though; the bods have done a good job. The R50 could have been quite frightening, but it's actually pretty well planted. The limiting factor isn't a loss of lateral grip - it's the wheelspin which you can so easily conjure up when you're not heading along a straight, flat, well-surfaced road, and which has to be quelled by frequent interjections from the traction control system.The best bit about the R50's behaviour, in my opinion if not that of other reviewers, is its ride quality. Body movement is well controlled, and the very low-profile tyres don't transmit nearly as much unwanted information as I was expecting them to (though they do wipe out the last vestige of the Touareg's claim to be an off-roader - don't even think about taking this thing into a muddy field).There is the small matter of price. Volkswagen is asking just short of £62,000 for the R50, and you'd have to be exceptionally keen on the idea before parting with that sort of money. For around £4000 less you could have a supercharged Range Rover Sport, which isn't as quick (despite being more powerful) but has much more badge appeal in this market sector. For a whopping £20,000 less you can buy a Jeep Grand Cherokee SRT-8, which is completely barmy but also a great deal quicker.Admittedly, those cars have petrol engines, and their combined fuel consumption figures are laughable at around 17mpg in each case. The relevant statistic for the diesel R50 is a more acceptable 22.4mpg, though you won't match that if you take advantage of more than a fraction of the performance.So why would you buy it? Well, it's fun, it's beautifully built, equipment levels are very high, it looks fantastic and flooring the accelerator pedal produces a very amusing effect. And you're unlikely to find another one parked on the same street. In other words, it's a rare toy, and I can see the attraction of that even if I can't imagine spending all that money on one of my own. Engine 4921 cc, 10 cylinders Power 350 bhp @3500 rpm Torque 627 ib/ft @2000 rpm Transmission 6 speed semi-auto Fuel/CO2 22.1 mpg / 333 g/km Acceleration 0-62mph: 6.7sec Top speed 146 mph Price From £63176.00 approx Release date 10/03/2008