Click here for more on Porsche

As we approached a blind bend at more than 100mph I realised just how big a mistake I had made. Getting in a Porsche with Walter Röhrl, four times winner of the Monte Carlo rally, seemed like a good idea at the time but the old boy had clearly lost his marbles.

There was no way the Porsche was going to slow in time to stop us flying off the side of the mountain a mile above the Mediterranean. With a following wind we might even touch down in Monaco. Nobody forced me to get into the damn car and, had I not been quite so keen to see just how fast this new Porsche would go, oblivion would not now be approaching at a three-figure speed.

The fact that I’m writing and you’re reading this is down to divine intervention and the fact that Röhrl hadn’t quite taken leave of his senses but had made a calculated judgment based on the roadholding abilities of the new £69,900 Carrera 4S.

Röhrl knows the passes above the principality better than I know the street outside my house (nobody has surpassed his four Monte Carlo wins) and he slithered round the bend at a speed I wouldn’t have tried on an empty racetrack. “As you can see,” he said as I peeled my sweat-soaked shirt from the passenger seat at journey’s end, “the car is very stable, even in quite extreme conditions.”

Enthusiasts know the 911 remains today what it has always been: the most practical supercar conceived. But never far from the minds of many is the lurking fear that 911s bite the unwary and unlucky. Over the years they have heard too many stories of 911 backs overtaking 911 fronts, resulting in 911-shaped holes in walls and embankments. Porsche 911 drivers think four-wheel drive protects them, but they’re wrong.

Still, there’s no denying that this latest generation of the 997-based Carrera 4 is a sizeable leap forward over the Carrera 4 of the 996 era that reigned from 1998-2004.

Visually the biggest change is that these new four-wheel-drive 911s gain special wide bodywork that pumps out the rear haunches by nearly 2in, meaning you won’t have to look at the badge on the back to tell which one it is. The body accommodates even fatter tyres and goes some way to justifying the £4,900 and £4,550 price rises over the standard-bodied Carrera S and Carrera respectively.

Mechanically it’s barely four-wheel drive most of the time, with only 5% of the power being diverted to the front wheels in normal conditions. It is only when the car starts to lose grip that up to 40% of the power can be shuttled forward to provide spectacular traction away from wet or tight corners.

Röhrl says the four-wheel-drive system takes him about his business quicker than he’d travel in a Carrera S, but for those of us who don’t live on top of mountains feasting on ambrosia, Porsche’s own figures say four is slower than two.

The 4S matches the S’s 4.8sec sprint to 62mph, but at 179mph the top speed is 3mph slower than the substantially cheaper 120lb-lighter S. The two-wheel-drive is more fun to drive and, thanks to its slimmer hips, easier to thread down a great road.

Which leaves me in the slightly strange position of being unable to recommend a car that dazzled me from the second I took its wheel to the moment I poured myself gasping from its passenger seat with a grinning Röhrl beside me.

Unless you like the wide body or truly need four-wheel drive, save the money and get a Carrera S. For as long as I’ve been doing this job I have maintained that if I had the money and could drive only one car for the rest of my life, it would not occur to me to get anything else. Fabulous though the Carrera 4S is, it gave no reason at all to modify that view.

VITAL STATISTICS

Model Porsche 911 Carrera 4S
Engine type Six cylinders, flat formation, 3824cc
Power/Torque 355bhp @ 6,600rpm / 295lb ft @ 4,600rpm
Transmission Six-speed manual
Fuel/CO2 23.9mpg (combined) / 285g/km
Performance 0-62mph: 4.8sec / Top speed: 179mph
Price £69,900
Verdict Quite exceptional: don’t buy one
Rating 4/5
THE OPPOSITION

Model BMW M6 £79,760
For Pile-driving performance from a great engine
Against More ultra-fast grand tourer than raw sports car

Model Maserati Coupé £56,650
For Name, engine and image to challenge the best
Against But not build quality or handling