The X6 is all well and good, so is the 7-series and so is the 5-series Touring. BMW insists, though, that if you make a triangle out of those three cars, the car that fills the space in the middle will be perfect for a lost generation of potential buyers who want some of each car, but not all.
So the 5-series Gran Turismo was built specifically to mop them up and, BMW evangelistically claims, to create an entirely new market segment - something the car industry really hasn't managed since the Renault Scenic.
So BMW"s got big claims behind this car, but it actually does offer 7-series front and rear leg room, luxury and entertainment features, as well as X5 head room, monster luggage space and cracking new engine and gearbox technology.
Whatís it like?
All of that evangelism can turn you off a car before you even drive it, but that would be a mistake with this car.
For starters, thereís the technology. It has the latest generation of 3.0-litre diesel, which is expected to comfortably outsell the 535i GT in Europe. It deserves to as well, because it has 241bhp of power at 4000rpm and 398lb ft of torque from 1750 to 3000rpm.
It will help that itís the cheapest Gran Turismo, but itís also the best of the GTís engine range.
But while itís not the fastest, it never actually feels wanting. Our side-by-side charges showed the 535i consistently pulling away, even in rolling in-gear sprints, but the 530d version was never humbled as it smoothly charged through its eight gears, swapping seamlessly regardless of whether the brilliant new transmission was in its softest or sportiest settings.
BMW claims it will pull 43.5mpg on the EU combined cycle, but we didnít come close to that. In fact, we comfortably halved it without even trying and, with only a 70-litre tank, the GT might be stopping to refuel more than weíd like.
Short-range tank apart, it will be a legendarily good cruiser. The engine idles at 700rpm, and at 62mph itís only ticking over at 1350rpm. At 80mph itís only pulling 1700 revs Ė which isnít even at the torque peak yet Ė and at 124mph itís still only around 2200rpm. Relaxed? You bet.
If the driveline is comfortable, the cabin backs it up, and then some. It will be the tank dictating your stops, not your back. The seats are brilliant, with soft initial cushioning and firm support beneath it Ė and that goes for all four of them (a bench seat, with a strictly temporary middle seat, is actually standard).
Itís almost better in the back, too. It sits on exactly the same wheelbase (and tracks) as the 7-series, so thereís plenty of space, but itís been cleverly worked on. The design of the dash and front doors flows beautifully into the rear, where the seats adjust fore and aft individually and so do their backrests. And BMW has rediscovered the joy of oddments storage space in the cabin.
BMW makes much of the rear hatch, which has a small opening that doesnít crack the passenger bulkhead and a big one that does, but the important thing is that the space is very flexible, with up to 1700 litres with the rear seats folded down.
All of that would mean nothing if the chassis wasnít this astonishingly good. At 1960kg, the 530d GT has every excuse to be a floppy mess. It isnít.
Dynamic Drive Control, which tweaks the gearbox, throttle and steering maps and the dampers, is standard and ranges from Comfort to Sport+ programs. Forget the extremes (Comfort is too wallowing and Sport+ is too aggressive on bump) and keep it inside Normal and Sport and youíll find a terrific chassis lurking here.
Itís balanced, it never gets unsettled, itís quiet, the ride quality is brilliant and thereís so much poise that itís difficult to imagine how youíd ever throw one away, aside from falling asleep in it.
Its only noticeable flaw Ė and, even then itís magnified out of all proportion by the quality of everything else it does Ė is the thumping noise out of the rear suspension as the air spring pushes its shaft back down on broken, square-edged holes. Itís like that, we were told, because the spring rate has been set for the car to run at its maximum load, which is 600kg heavier than as tested.
Should I buy one?
That depends on a lot of things about you, such as what you need, what you donít need and how big your parking space is.
Donít automatically nay-say it, though, because it doesn't feel like a 5-series and it doesn't feel like an X5, either. The driverís hip point sits exactly between them, and so does the whole feel of the car.
The front suspension is pure 7-series, the rear is from the next generation of 5-series Touring and somehow theyíve been combined to make the GT feel as though it does indeed occupy its own turf, yet it still feels like a BMW.
It ends up being a car that is just so crackingly good that you forget everything BMW has tried to convince you of and just respect is as a superbly engineered machine. Because it is.
Definitely a drive-it-before-you-discount-it proposition.