Porsche Cayenne Turbo S

That also applies to the price tag of £81,565 - nearly £11,000 more than the already-rapid Turbo version. Can it really be worth such a huge premium?

At a glance, only 20-inch alloys, oval exhausts and a badge on the boot set the S apart from other Cayennes. Inside, there's leather trim, DVD sat-nav and a BOSE stereo. But it's under the bonnet where the real work has taken place. Engineers have upgraded the intercoolers and the turbo boost to get an extra 71bhp from the 4.5-litre V8, taking peak power to 521bhp and torque to 720Nm.

Hooked up to a six-speed automatic gearbox, the engine propels the Porsche to 62mph from rest in 5.2 seconds (down from 5.6 seconds), and the Turbo S covers 50-75mph in fifth gear in only 5.4 seconds - 0.8 of a second quicker than the Turbo. Economy remains at a thirsty 18mpg. Cruising along Dubai's deserted highways in sixth, the latest Cayenne proved a relaxed machine, but change down and the acceleration is phenomenal. The engine shrugs off the SUV's 2,355kg kerbweight, pinning you in your seat. Without a doubt, this machine feels every bit as fast as its figures suggest.

To cope with the additonal pace, the company has fitted improved brakes,although the air-suspension, electronic dampers and adaptive four-wheel-drive system are left virtually unchanged.

In Normal and Comfort suspension modes, the S is refined, yet switch to Sport and you can corner quickly. With the suspension raised, the off-roader had no trouble tackling Dubai's sand dunes.

However, apart from the slight boost in performance, the biggest difference between the S and other Cayennes is price. Still, for those for whom money is no object, this is the ultimate SUV.