THE Porsche 911 is not only one of the world’s best-selling sports cars for more than 50 years but also a benchmark for others to aim for and, indeed, the definitive Porsche.

New incarnations of this iconic car have seen the introduction of a range of flat-six turbo-charged engines, advances in chassis performance and improved in-car connectivity, but the song remains the same. This is the epitome of sports car motoring.

Porsche has no intention of resting on its laurels in 2016. There's a new 911 R, for example, armed with a 500hp four-litre naturally-aspirated flat-six engine driving the rear wheels and six-speed manual transmission. Priced from £136,90, it is also limited to 991 units worldwide and is arguably the ultimate road-focused 911.

The new generation of 911 models includes the 911 Carrera, 911 Carrera 4, 911 Targa and the range-topping 911 Turbo and Turbo S.

Even with their extra potency, advances in technology, new platforms and predominantly aluminum construction, this so-called 991 Series is still recognisable from sketches drawn by Ferdinand "Butzi" Porsche in 1959.

At the top of the 911 tree lurk the Turbo and Turbo S, which now have increased horsepower and better driving dynamics through a boost function and now standard sport chrono package to improve responsiveness.

The power on tap is awesome. Both the Turbo and Turbo S come with a twin-turbo 3.8-litre six-cylinder engine, and while the 911 Turbo has a mightily impressive 540hp, there's a further 40hp to play with in the Turbo S.

The sport chrono package includes four programme, together with a sport response button on the steering wheel which a motoring colleague referred to as the "mental button". It offers the ability to adjust the vehicle's responsiveness to be "extremely direct" at the touch of a button for overtaking manoeuvres.

The result is that the Turbo sprints from 0 to 62mph in 3.0 seconds and the Turbo S achieves sub-three seconds nirvana, registering 2.9 seconds. These things matter in the rarified world of sports car heaven.

A quick look around the exterior reveals a new front-end design with side airblades and narrow LED lights, new 20-inch wheels with an extra half-inch width for the Turbo model. At the rear the changes include three-dimensional lights with four-point brake lights and modified dual tailpipes, while those with a keen eye might spot the new door handles.

The cabin remains a seductive leather-laden place to be, but with fresh techno twists. Online navigation and a top-notch touchscreen bring Google Earth and Google Street View into play and the system can be networked with a smartphone to access more apps.

There's a lot to take in - not least from the information overload in five sets of dials in the instrument panel behind the steering wheel.

But out on the road, where the car behaves beautifully in virtually any circumstances, there's one figure that demands your attention above all others - your speed.

With crushing acceleration available at the prod of your right foot, there's a need to go easy on the accelerator pedal and simply enjoy the relatively subdued but unique engine noise and the admiring/jealous glances of your fellow motorists.

Porsche offered me the chance to take half a dozen 911s around a circuit at its Silverstone race track experience centre. What impressed as much as the startling acceleration was the grip and traction of the car and the ability to brake safely and quickly from high speeds.

Porsche has made a plethora of advances in safety and comfort technology, including stability and traction management systems that come as standard and a post-collision braking system that reduces the severity of collisions.

On the Turbo models you can even have a 40-millimetre lift system for the front suspension to avoid those pesky speed bumps.

All these improvements take the 911 to another level, yet it remains a very pure product and one with which the British sports car enthusiast has had a half-century love affair. UK sales were up 30 per cent last year, and more than 18,000 guests enjoyed the track experience at Silverstone.

The 911 remains not only the ultimate Porsche but also for many the ultimate sports car. Look out for more Porsche changes in the next three of four years than in its history.