NEW generation all-wheel-drive 911 Carrera 4 and Carrera 4S coupes from Porsche are the latest addition to the 911 model family and perpetuate a long and successful tradition.

Porsche's legendary 959 model and the first Carrera 4, which dates from 1988, were early evidence of this manufacturer's competence in all-wheel-drive technology.

The most striking feature of these new 911 models is that they are 44mm wider over the rear arches.

The rear wheels of the Carrera 4 can therefore be fitted with 295/35 ZR 18 tyres, and its "bigger brother" with 305/30 ZR 19 tyres.

Powered by the proven 3.6-litre six-cylinder engine which has an output of 325bhp, the Carrera 4 accelerates from 0 to 62mph in 5.1 seconds and has a top speed of 175mph.

The 4S model, with a 3.8-litre engine developing 355bhp, can reach 62mph in 4.8 seconds and has a top speed of 180mph.

The all-wheel-drive system has a multi-disc viscous coupling and transfers between five and 40 per cent of the tractive force permanently to the front wheels.

This endows the two new coupes with excellently balanced performance, up to - and beyond - the limits of adhesion, increased straight-line stability and improved traction on slippery roads.

Porsche stability management (PSM) now has two new functions: the brake system is pre-filled ready for a full brake application, thus eliminating the air gap between the pads and the disc and making stopping distances even shorter.

The second new PSM function is activated if the driver depresses the brake pedal quickly but not forcefully. In this situation, the hydraulic pump builds up extra pressure to bring all the wheels into the anti-lock braking range and ensure optimal braking.

In its regular setting, Porsche active suspension management (PASM) offers a sporty but comfortable basic shock absorber setup, but operation of the sport button activates a noticeably firmer mapped setting.

In both settings, however, the suspension ratings are matched at all times to the driving style and road conditions.

The active shock absorber system is a standard feature on the 911 Carrera 4S and an optional extra on the Carrera 4.

On request, both models can also be fitted with sports suspension to lower the body 20mm closer to the ground; this option includes a mechanical rear axle differential lock.

The optional Sport Chrono Plus package is also available for the new all-wheel-drive models. It modifies the engine management characteristics and the control behaviour of the PSM and PASM systems.

The 911 Carrera 4 will be priced at £62,930 and the 911 Carrera 4S at £69,900 and will be available in the UK from late October.