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Engine options, top speed, acceleration and refinement

It’s a measure of how potent this SUV feels from behind its thin-rimmed wheel that our first thought was to dig out the road test figures recorded for the latest BMW M5.

Unsurprisingly, there’s daylight between the two, the Porsche setting a 0-100mph time of 9.3sec versus a blistering 7.5sec for its super-saloon compatriot and a fourth-gear 30-70mph time of 5.9sec versus 4.0sec, but when you’re marshalling 2307kg and sitting so far above the road, the larger car’s rapidity is nevertheless startling.

Porsche Surface Coated Brakes are standard but our test car had carbon-ceramic discs (£4217). The vast calipers each use 10 pistons and their expensive compound is denoted by yellow paint

A fairer comparison can be made with the Range Rover Sport SVR, which in 542bhp pre-facelift guise (an identical output to this Cayenne Turbo) could manage ‘only’ a 0-100mph time of 10.3sec with 30-70mph in fourth dispatched in 6.4sec. Our only real criticism is that the Porsche wins the pace race with so much less in the way of pomp and aural excitement than the supercharged Brit.

The abrupt manner in which that speed is shed is almost as impressive as the way the Cayenne piles it on in the first place. Carbon-ceramic front brake discs of 415mm, gripped by no fewer than 10 pistons at the front axle, helped to bring the car from 70mph to a standstill in 44.5m – a car-length sooner than its Range Rover Sport SVR rival – and with minimal nose dive. Indeed, it is the Cayenne’s stability and predictable nature under even the very heaviest braking that allow you to exploit the performance of the engine without hesitation.

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For the most part, ZF’s eight-speed transmission is almost imperceptibly fluent and better resolved to the car’s character than a dual-clutch set-up could ever be. Several testers nevertheless commented on the powertrain’s conspicuously languid response and conservative gear selection at suburban speeds when left in its default Normal mode. As such, you need to be ready to squeeze the left-hand gearshift paddles to pull into a gap in traffic, for example.

As part of the Sport Chrono package, there are three modes: Normal, Sport and Sport Plus. A Sport Response button also primes the powertrain for hair-trigger reactions for up to 20sec, although with so little in the way of turbo lag at higher engine speeds, it’s hardly required.

Adding to the Cayenne Turbo’s impeccable long-distance credentials is a touring economy of 31.5mpg, which is very acceptable for a 2.2-tonne SUV with a twin-turbo 4.0-litre V8. Together with a 90-litre fuel tank and aided by the car’s ability to decouple the engine and transmission for periods of off-throttle coasting, that allows a touring range of almost 625 miles.