GVC has been designed to be imperceptible, which is lucky, because we couldn't detect a thing. Apparently we're talking about differences of 0.01-0.05g when entering corners, and it isn't intended to make the car handle better on the limit, just to make the whole process of cornering easier and more stable.
Either way, the Mazda 6 remains one of the better-handling cars in the class, benefitting from quite light but linear, precise steering and an eagerness to turn in to corners not always demonstrated by its rivals. It also takes a lot before the front wheels begin to protest and give up grip, and for what feels like quite a large car from behind the wheel, its body stays propped up nicely. Ultimately a Mondeo Estate is more rounded dynamically, but the 6 isn't far short.
The 148bhp version of this diesel seems to make the most sense. Work has been done to reduce turbo lag and improve torque delivery, and while it's difficult to detect this over the old car, the lesser of the two diesels remains happy to pull from 1800rpm and doesn't suffer too narrow a band on song. The 168bhp version is quicker in a sprint and in gear, but not by enough to warrant the extra cash needed to buy and run it.
Mazda has also worked on diesel refinement. It has revised its 2.2-litre unit's pistons to ensure less vibration and fiddled with the injector timing in an effort to cancel out some of the engine's higher-frequency sounds. There are also upgraded door seals and sound-deadening materials throughout. The results in this department are more obvious: the 148bhp model we tried felt smoother and quieter under load than before, although it's still not class-leading in this respect, even if the fluid feel of its manual gearbox just might be.
Decent agility is mixed with a commendable ride. Our test car wore 17in alloys, which picked up on some of the sharper ruts of our Spanish test route but got better with speed to provide a cosseting motorway cruise. Having also tried the larger 19in wheels, which add more fidget without much dynamic gain, we'd say the former are the way to go.
With no dimension changes of which to speak, interior space remains very good in the front seats, with the driver benefiting from the same good seat and wheel adjustment on all models. Two more adults will sit comfortably in the rear seats, although a Skoda Superb does a better job, and the Mazda's 522-litre boot has the low loading lip, folding rear seat levers and flat floor you'd expect, but not the Skoda's outright space.
All 6s now come with a new leather steering wheel and upgraded dash trims, which, together with Mazda's continued competence at creating slick, substantial switchgear and one of the class's best infotainment systems when it comes to ease of use, makes the 6's cabin an even nicer place in which to spend time than it was before.