IT'S the car that broke the mould at Porsche by becoming the German auto maker's first four-door model and SUV.

That was some 20 years ago - and the Cayenne has gone on to become one of the brand's top sellers.

Now it is in its third generation and has gone on to notch up well over a million sales since its launch in 2002.

It has also become a trailblazer - and pace-setter - for the brand which built its reputation on performance cars.

For an SUV, the Cayenne has become a legend - a full-blown off-roader yet with a turn of speed that would not shame a supercar.

The current version is available in a variety of guises ranging from 3.0-litre V6s to mighty twin-turbo 4.0-litre V8s pushing out an awesome 640ps.

Bring in some electrification in the form of plug-in hybrid power and that output can be increased to a whopping 700ps.

With a blistering 0 to 62mph acceleration time of just 3.3 seconds and a top speed of 186mph the Cayenne Turbo GT is the quickest of the current line-up and is a 2.3-tonne SUV that can show a clean pair of heels to many a Ferrari.

The Turbo GT is the flagship Cayenne and priced from £147,510 - a figure more than double that of the entry level model in the current range.

Sumptuously appointed, the Turbo GT is the epitome of the model that transformed Porsche's fortunes in a new world of automotive design and manufacture.

The Turbo GT we sampled came with almost £9,000 of extras fitted including a £1,700 paint job, a £1,000 head up display and a £2,000 automatic cruise control system with lane assist function.

That took the cost to a smidgen over £156,000 - a heady increase from the £45,000 it cost to buy the 2005 Mark 1 Cayenne S from Porsche Classic we also got the chance to drive.

Handling is a Porsche forte and whether it be the mighty Turbo GT or the original version both excelled.

Air suspension has always been a standard feature on the Cayenne as has the Porsche Active Suspension Management system and combined they deliver fantastic ride characteristics whether on the road, the track or in the mire.

Multiple drive modes with settings for normal, sport, sport plus and individual give a marked difference to the feel of the Cayenne and there's also an overboost facility which unleashes maximum power for 20 seconds.

Dynamically the Cayenne is sublime and the Turbo GT embodies all that makes Porsches so exceptional.

It's little surprise that the Cayenne Turbo GT has lapped the 13 miles of the Nordschleife at Germany's Nurburgring in just 7:38:925 minutes - quicker than a Bugatti Veyron.

Despite its SUV proportions - this particular Cayenne is some 4.9 metres long and almost two metres wide - there's a proper cockpit feel from the driving seat.

High tech equipment includes state of the art instrumentation centred on a rev counter but smart enough for the navigation display to switch into view as and when needed.

That's as well as a large central display screen which sits on the dash above a centre console fitted out with haptic controls either side of the gear shift.

It's as intimate as the feel you'd expect from a two-seat sports car in a cabin that is large enough to take four in considerable comfort.

Boot space is as practical as in any SUV and ranges from 549 to 1,464 litres while from a styling perspective the Turbo GT is distinguished with large front air scoops, a power bulge on the bonnet and an active rear spoiler.

Fuel economy for the performance flagship of the Cayenne range with its eight speed automatic transmission is rated at 20mpg with emissions of 319g/km - a figure which we slightly bettered on our drive seeing an average of 20.8 to the gallon recorded on the trip computer.

An almost 20 gallon fuel tank is fitted so range is not an issue.

In every way it is a super car in the SUV market and since the original transformed Porsche's fortunes it has gone on to galvanise other luxury brands such as Bentley, Lamborghini and Mercedes to flirt in the 4x4 perrformance zone.

In keeping with the current trend for zero emissions, an electric version of the Cayenne is under development - there Is already a plug-in hybrid capable of some 74mpg - and is due for release in 2024, shortly after the arrival of the EV variant of the Porsche's smaller SUV, the Macan.