What is it?
Can't say we're totally sure. The cosmetic changes are small - there are new ‘eyebrows' over the headlights, and the GT's rear end is less bulky because the bumper's been tucked in. Although weirdly the internal boot volume has still grown to 500 litres.
And the engineering tweaks aren't exactly ground-breaking either. The biggest news is that all the engines are now Euro VI compliant (Euro VI is the new EU emissions legislation that comes into force in 2014). With the diesels, this has been achieved by various post-combustion processes, such as the addition of a urea trap to the exhaust that mops up harmful NOX gasses.
For the vast majority of the petrols, BMW has tweaked the injectors. They're now smaller with even teenier holes, so the ECU can control the fuel flow much more accurately when the car is warming up. Also, the turbo waste gates are now opened by an electric motor.
See more pics of the new BMW 5-Series GT
I'm bored. How does all this actually affect me?
Not by much, unless you live in America. In the US, the V8 GT is one of the more popular models, so it was worth BMW changing the engine to the latest Valvetronic motor. As such, power is up by 10% to 444bhp, while fuel economy has dropped by 17% to 32.8mpg.
Elsewhere, the alterations to the engines are so minor that the differences in power and fuel economy between the previous gen and this one are negligible. It might meet Euro VI, but that makes little difference to anything you'll notice day to day.
For the record, the 535i that we drove had 302bhp, 295lb ft, 34.6mpg and 192g/km. The only change is the fuel economy, which has dropped by a whopping 0.2mpg. Like, wow...
You don't sound very enthusiastic?
We're not. The 5GT was always an odd BMW, and this facelift is so insignificant that nothing has changed. It will still appeal to its natural markets in China and the US, but in Europe it'll remain a rare thing, especially if you factor in the premium that BMW charges for the GT range. Our 535i Lux is £49,015.
If you need a spacious 5-Series, buy the Touring.