What are you driving?
The diesel version of BMW's 6 Series Gran Turismo (6 GT), which we drove in petrol format as the 640i xDrive just a few days ago. That 340hp petrol car is unlikely to find many buyers here in Ireland, where its road tax implications and high list price will make it a rarity. The 630d is usefully cheaper than the 640i, as well as offering lower running costs thanks to its reluctance to guzzle fuel as readily as the range-topping 6 GT. So does this diesel coupe-hatch-luxury-limo mash-up convince us of the merits of opting for one of these unusual things, over and above the incredibly talented 5 Series Touring?
Name its best bits
Like any 6 GT, the 630d remains supremely refined on a cruise. In Comfort Plus mode, it can whisper along a motorway in a state of near-ethereal calm, thanks to acoustic glass wrapping around the front of the cabin, masses of sound-deadening packed into the underbody and that glorious BMW straight-six diesel, which dies away to the point of silence on a trailing throttle. So if you want to go mega-miles in the ultimate of comfort, then the 630d is even better than the 640i, mainly because its fuel economy is so much better and therefore it has a far greater potential range between fill-ups.
And the diesel loses nothing on the interior ambience front to the petrol, as you can still make a loaded-up M Sport model feel extremely opulent within. Gesture control infotainment, head-up displays, massaging and ventilated seats, a digital instrument cluster... they're all on the menu. Even though this test car was rear-wheel drive, as opposed to the 4WD-only 640i, there's no extra boot space, but that's no problem as there's a colossal trunk on the GT and acres of interior room too, so it does perfectly fulfil its 'luxury limo with hatchback practicality' brief.
Anything that bugs you?
When even the M Sport model makes 20-inch alloys look diddy, then you know it's a piece of automotive styling that hasn't really worked - and that's about the kindest thing we can say of the BMW's aesthetic value. Dark colours do help it somewhat, but they don't make it pretty.
And the switch to only two driven wheels does nothing for the dynamics of the 6 GT. It remains too inert, too prone to understeer before all else, that it doesn't truly feel like the sporty coupe BMW reckons it is. It's all well and good saying a 5 Series Touring isn't quite as luxurious as this, but the wagon has a far nicer chassis and it's a much more elegant machine on the outside. Similarly, a 7 Series would ride every bit as well as the 6 GT and yet it steers in a sweeter fashion.
And why have you given it this rating?
The 630d is really no better nor worse than the 640i xDrive. If what you want is unfailing ride comfort above all else, the 6 GT can do that and do it very well. But it's expensive compared to a 5 Series Touring, it's not as good to drive as the even-more-cultured 7 Series saloon and you have to put up with its ungainly exterior as a consequence. If you can get past the styling, give the 6 Series a whirl. Otherwise, look elsewhere in the BMW range for better all-rounders.
I want to know more
If there is anything specific you'd like to know about the BMW 6 Series GT that we've not covered, feel free to send us a question via the Ask Us Anything page.
