The BMW 5 Series Gran Turismo (or 5 GT) has traditionally been available only with relatively thirsty six- and eight-cylinder engines.
Now, though, BMW has slotted its frugal 2.0-litre four-cylinder diesel under the bonnet of this big executive hatchback to create the 520d GT.
The new model averages 53.3mpg and 139g/km of CO2, a significant improvement on the 43.5mpg and 173g/km of the next most efficient 5 GT, the 530d.
What's the 2012 BMW 520d GT like to drive?
The 5 GT weighs almost 200kg more than the 5 Series Touring, so BMW's 2.0-litre diesel engine has a fair bit of extra work to do. It acquits itself well, though, delivering the sort of acceleration that allows stress-free overtakes when needed.
The GT's bulk is more obvious when you turn into a bend or brake. Engine refinement is more impressive, but there's too much wind noise at speed, and road- and suspension noise intrude over rough surfaces.
However, the steering isn't as sharp as you might expect from a BMW, and the firm suspension makes the ride unsettled, but still allows a large amount of body roll.
What's the 2012 BMW 520d GT like inside?
The cabin of the 5 GT is built from high-quality materials and most functions are controlled through BMW's intuitive iDrive system.
There's plenty of space for six-footers in both the front and rear, but rear visibility is restricted due to the 5 GT's steeply sloping rear screen with blacked-out side windows.
BMW has also put a foldable bulkhead between the cabin and the boot, which makes dropping the rear seats a long-winded experience.
The tailgate opens in the style of both a hatch and a saloon, but the 5 GT has a relatively modest 440-litre boot capacity when its rear seats are in place; a 5 Series Touring gives you 560 litres.
Should I buy one?
This is the best version of the 5 GT, because it offers all the performance you need and is the cheapest to buy and run. However, a 5 Series Touring is cheaper, more enjoyable to drive and more practical, so it's a much better option.
Alternatively, if you're after a stylish four-seater with hatchback practicality, we'd urge you to consider the Audi A7 Sportback.
Audi A7 Sportback
BMW 5 Series Touring
What Car? says