WITH a reputation as one of the best saloon cars to drive and having undergone a well-received complete makeover just over three years ago, the Mazda6 already had a lot going for it.

Things move quickly in the modern-day motor industry, though, and resting on your laurels for too long is simply not an option.

The unstoppable rise in popularity of the crossover and SUV, plus newer versions of closer-matched rivals such as the Ford Mondeo and Skoda Superb, have continued to increase competition for the 6, prompting Mazda to respond with a series of upgrades for 2017.

Try to spot the difference from the outside, however, and you'll be flummoxed, while visible changes to the interior are also so subtle as to be negligible.

That's not a problem. The 6 was already one of the most eye-catching family saloons on the road and the cabin perfectly comfortable and roomy - so if it ain't broke why fix it.

The key updates to the new Mazda6 all happen out of sight and are designed to improve driving dynamics, stability and enjoyment.

The big change is the introduction of what the Japanese brand is calling G-vectoring control, or GVC for short.

This system constantly monitors steering and throttle input, especially when cornering under power, and adjusts the balance of torque delivered to the front wheels, thereby transferring a fraction more weight onto the front axle, which allows the front wheels to turn more precisely.

Even on a straight road, according to Mazda, GVC can reduce driver fatigue and increase passenger comfort by removing the perceived need for the tiny steering corrections that many of us continually make.

In all honesty, it is difficult to tell just how much of an affect the GVC has had without driving new and old versions of the 6 back-to-back, but it is safe to say that this is still one of the most engaging and entertaining saloons to pilot.

Steering is direct and quick, acceleration prompt and decisive and grip solid and assured. Enthusiastic drivers will be able to push on with confidence, enjoying the nimble responsiveness and balance of the chassis - which offers great stability.

An unchanged engine line-up features a choice of four powertrains - 145ps and 165ps 2.0-litre petrol units and 2.2-litre 150ps and 175ps diesels - mated to either six-speed manual or automatic transmissions depending on model selection.

With the diesels accounting for around 75 per cent of UK sales, Mazda has also tweaked that power pack to reduce noise which, coupled with improved sound insulation, makes the 6 a much quieter car generally and a particularly refined cruiser.

Performance is pleasingly punchy, even with the lower-powered oil-burner which I drove, with the 0-62mph sprint coming up in a sprightly 9.0 seconds and a top speed of 131mph, while fuel economy of 67.3 miles per gallon on average is competitive and will tempt the business buyers who dominate this class.

The manual transmission on this range-topping Sport Nav spec car had a smooth and snappy action which served to enhance the feeling of driver involvement.

There's a greater choice of colours for the new Mazda6 (now up to eight) while inside there's a new leather steering wheel that on Sport Nav models is also heated.

Other upgrades to range-topping versions include an enhanced head up display which is now in colour and features traffic sign recognition and a new colour TFT dial.

Equipment levels are also enhanced in mid-range SE-L Nav models which now get auto power-folding mirrors while Mazda's smart city brake support low-speed collision mitigation system now features pedestrian recognition.