Both versions share a brand new Porsche six-speed Tiptronic S transmission - although the Cayenne S will later be available with a manual gearbox - and a completely new permanent four-wheel-drive system that owes nothing to current 4wd Porsche models. The Cayenne will also get a more sophisticated version of Porsche Stability Management (PSM) that will juggle both the brakes and the transmission split at the outer limits of the car's ability.

Surprisingly, given the car's sporting credentials, the transmission is fitted with inter-axle diff locks and additional low-range gears to give it better traction in tricky conditions. Porsche is being coy on the details of the braking system needed to cope with this two-ton car, but it has stated that the Cayenne underwent the same testing procedure as any other Porsche and will continue the company's reputation for the best brakes in the business. However, expensive ceramic brakes will not be available, even as an option.

The Turbo version has certain visual differences that distinguish it from the normally aspirated Cayenne S; its nose has dramatically larger air intakes to feed the intercoolers and larger radiators, together with twin power bulges on the bonnet and four exhaust pipes at the rear. It also comes on 20-inch wheels, rather than the 18-inchers on the S, and sports red brake callipers inside the enormous rims.

It's a huge car - longer and wider than BMW's X5, though not quite as tall. Initial reaction to the styling has been muted. Porsche has tried too hard to incorporate the familiar family look, but it sits slightly awkwardly with the 4x4's upright stance. The slab sides and squared-off doors seem to fight with the rounded, 911-like rear haunches. The back of the car looks the tidiest piece of design with a large tailgate, complete with opening rear window, giving access to the boot, though there's little to tell you that this is the new Porsche. That could be a problem as the stated aim of the car is to tempt Porsche enthusiasts to stay with the brand when family commitments have previously forced them to look elsewhere.

But although the European market may be hard to crack, America is sure to love the Cayenne and Porsche is confident it'll soon build up a waiting list for the 25,000 cars a year it plans to build. In the UK the first six months' allocation has already been sold, and that's before prices have even been announced. Despite some scepticism, maybe Porsche has got it right again.