Porsche 911 Carrera 4S

A sensible Porsche 911? Something doesn't sound quite right here…

Price: £87,959
Engine: 3,800cc, flat-six cylinders, 24 valves, 400bhp
Transmission: Seven-speed gearbox, four-wheel drive
Performance: 189mph, 0-62 in 4.5sec, 29.7mpg, CO2 224g/km

A four-wheel-drive 911? It might sound strange, but there can be more to a four-wheel system than just the ability to haul a vehicle over tricky terrain.

Nor is an all-wheel-drive Porsche 911 anything new. The first 911 Carrera 4 arrived in 1989, its drive system inspired by that of the turbocharged Porsche 959 supercar that could reach around 200mph. Now, as then, the idea is to share the power as well as the grip between all the wheels as required, which can be useful when – as here – that power amounts to a hefty 400bhp.

Sounds sensible, and arguably attractive for the extra £6,700 if snow and slipperiness are often to be found under your 911's wheels. But that "sensible" word brings up a conflict when 911s are involved. That's not just because they are fast, expensive and sometimes evoke hostile thoughts in other road users. It's because a 911 remains the only car left with a rear-mounted engine, a design which physics says is innately unstable.

The whole 911 story since the first example appeared in 1963 has been about making the design work and the challenges it has posed to the driver. Here lies much of a 911's attraction, as you pit your skill against the treacherous auto-beast, and feel the thrill as its tuneful flat-six engine sings its song.

In essence, the thrill hasn't changed much over the years, but two facets of this latest example undermine that foundation. The first is that a year ago, Porsche thoroughly revamped the 911 for only the third time, making it larger yet lighter, more comfortable and quieter. One change was to include electric power-steering because it uses less energy than an older hydraulic system, but in doing so Porsche deprived the 911 of some of its unique tactility.

The second is the four-wheel drive, suggesting that this option – newly available on the third-generation 911 – is aimed at drivers concerned more with image than thrills. This Carrera 4S may be a brilliant car, but is it a brilliant 911?

The S part, by the way, denotes that 3.8-litre, 400bhp engine; a Carrera 4, cheaper by £10,000, makes do with 3.4 litres and 350bhp, which are probably fine for most purposes.

Anyway, back to the 4S, and such is the mighty pulling power of its engine that you use the long-legged seventh gear entirely naturally, which helps keep the economy at a level able to place the C4S just under the max-tax band. Sport and Sport Plus buttons firm up the ride and sharpen the engine's responses; these modes also make the exhaust noisier but you can switch that toy off separately. This car sounds delicious even in "quiet" mode.

And the four-wheel-drive part? Mostly this 911 feels, and is, pushed along predominantly by the rear wheels, but myriad sensors tell the systems to divert torque towards the front wheels when the rears are feeling overwhelmed. That is on top of the other traction-control systems, and a dashboard display can tell the driver what is happening. You can feel it working as the 911 scythes through a wet roundabout, generating grip extraordinary for the conditions.

It is a supremely capable, confident, comfortable grand tourer which is extremely easy to drive quickly, very quickly, should the chance arise. It's your best friend on a wet, windy night. It's brilliant. But does it take away from the 911's essence? For me, it does; it feels too "normal". My favourite 911s will always be propelled by the rear wheels alone.