Look at this new Porsche 911 GT3 on paper alone and you could be tempted – forgiven, indeed – to think we’ve been here before. Meet the new boss, same as the old boss. Or near as makes not much difference. Bit heavier, bit more powerful, a lot more expensive. Flat six, no turbos, two pedals or three. Nothing to see here, move right along.

And what a mistake that would be. Because when you drive it, and for reasons we’ll be getting to directly, you realise it is one of the most-changed GT3s of them all. The most? The improvement from first to second generation of the original 996 was undoubtedly larger, but conceptually and in the way the car now begs to be driven? Yes, I’d say so. But space is short and the changes are many, so join me for a quick charge around what is, if nothing else, the most surprising GT3 I’ve driven.

The 4.0-litre engine has gained 10bhp and in power terms now precisely splits the difference between the 493bhp previous GT3 and its 513bhp GT3 RS sibling. Weight has gone up a paltry 5kg, which would have been nearer to 40kg had Porsche not gone above and beyond to keep mass under control.

It has, however, managed to save 6kg in the engine, 10kg in the exhaust system and the same amount by using a lithium ion battery. A further 4.7kg comes with thinner glass, 2.5kg using a CFRP bonnet, 3.5kg with lighter engine mounts, 1.9kg by having less sound-deadening material, and the rear deck is 0.5kg lighter. The forged alloys save 1.3kg. You can save almost as much again if get trigger happy with the options and spec ceramic brakes and seats and a roof made from CFRP. Be warned, however, that those three innocent ticks alone add more than 10% to the price of the car.

But there’s an even bigger change to the aero package, which is, I think, the first on a GT3 to generate sufficient downforce for Porsche to want to discuss in numerical detail. The new rear spoiler looks odd with its ‘swan neck’ mounts, but it’s that way because it’s the underside of the wing that does the most work, so keeping its surface clean makes more downforce.

There is, of course, a new front spoiler, but you have to jack the car up and whip off a front tyre to see how the front diffuser now manages airflow around the wheel well and can be adjusted to balance out changes of rear wing angle. With everything at max attack, it develops 385kg of downforce, some 150% more than the old GT3 in the same configuration.

That’s a big deal, but not as big as the other change you’ll see when that alloy is off the car. For there at the front is the first double-wishbone suspension unit to grace a street 911 in the 58-year history of the car. Indeed, if you want to drive another 911 with wishbones, you’ll need to spend one million bucks on a Le Mans-spec RSR racer. Literally. This profound change of approach has meant the multi-link rear suspension has had to be entirely redesigned too, because otherwise the four-wheel steering system would not have worked as required.