What is it?
Consider the facts. Here’s a car that weighs 2215kg and yet it can dispatch the benchmark 0-62mph sprint in just 4.5sec – a time that matches that of the latest Porsche 911 Carrera S. With less than flattering aerodynamics, it also manages to achieve a top speed of 176mph.
The latest of Porsche's second-generation Cayenne models can also hold its own off-road. It comes with multi-stage air suspension that gives 273mm of ground clearance in its highest setting and some impressive four-wheel drive hardware, including the latest in electronic torque vectoring to juggle drive between individual wheels at the rear.
Among the Cayenne Turbo S's true highlights is a lightly reworked version of the blown V8 petrol engine found in the standard Cayenne Turbo – a potent proposition in its own right. The same unit also sees service in the monstrously fast Porsche Panamera Turbo S.
There are other subtle power-enhancing tweaks, with the 4.8-litre, 90-degree direct-injection unit receiving a more free-flowing inlet manifold, increased turbocharger boost pressure and remapped electronics.
Power climbs by 49bhp, peaking at 542bhp to make this not only the fastest but also the most powerful iteration of the Porsche off-roader to ever see series production. Torque is also up by 37lb ft at 553lb ft – developed on a band of revs between 2250 and 4500rpm.
Unlike in the Porsche Panamera Turbo S, which uses a seven-speed, dual-clutch PDK gearbox, the heady reserves are channelled through an eight-speed Tiptronic automatic transmission with a conventional torque converter to all four wheels.
What is it like?
The upgraded engine provides the Cayenne Turbo S with relaxed qualities at around town speeds and extraordinary pace when the conditions allow. It's a remarkably refined and easy car to drive in all weather and all seasons.
Best of all, though, the performance gains come without any change in combined cycle fuel consumption, which remains at 24.6mpg.
Porsche quotes incremental improvements in the 0-62mph sprint time and top speed over the Cayenne Turbo. But they fail to convey the explosive rush of acceleration you're subjected to on a heavily pegged throttle. It dispatches big distances in an urgent manner, with impressive straight-line stability.
There is a somewhat firm ride that can sometimes turn uncomfortable and introduce some nasty tyre rumble on less than smooth road surfaces, even in Comfort mode.
Direct electro-mechanical steering, superb damping control and strong grip also provide it with impressive agility for such a big car.
With the suspension switched to Sport mode, in which the ride height is lowered to 183mm to reduce the overall centre of gravity, it carves through corners with impressive directness, control and great purchase.
Should I buy one?
There will no doubt be some who see the new Porsche Cayenne Turbo S as nothing more than a four-wheel irreverence; a playtoy. And with a price tag of £107,460, a rather expensive one at that.
But they're missing the point of what is perhaps one of the most capable off-roaders ever built. In pure engineering terms, it is among the most impressive road cars.
That said, the Turbo S lacks the sharpness and response of the much-cheaper, £67,147 Porsche Cayenne GTS, which on overall balance remains the pick of the line-up, even though it lacks the Turbo S's unbelievable pace.
Porsche Cayenne Turbo S
Price £107,460; 0-62mph 4.5sec; Top speed 176mph; Economy 24.6mpg; CO2 emissions 270g/km; Kerb weight 2215kg; Engine V8, 4086cc, twin turbo, petrol; Power 542bhp at 6000rpm; Torque 553lb ft at 2250rpm; Gearbox 8spd automatic