New BMW 3 Series GT vs rivals
True, it doesn't look as rakish as the GT, but it's roomier than rival wagons from Audi, Mercedes and Volvo, and sets the benchmark for running costs and driving manners.
Another car that you might want to consider is Audi's A5 Sportback. Just like the 3 GT, the A5 has a seriously practical, hatchback-style boot, yet it has more of the appearance of a coupe than a family car from the outside, thanks to its sleek lines and sweeping, low-slung roofline. All of the cars on this test are powered by tax-friendly 2.0-litre diesel engines.
The cars on test:
BMW 3 Series Gran Turismo (GT)
BMW 320d Touring
Audi A5 Sportback 2.0 TDI
What are the 3 Series GT, A5 Sportback and 3 Series Touring like to drive?
Our 320d GT came equipped with adaptive M Sport suspension (a £750 option), which allows you to vary the stiffness of the shock absorbers. However, even when this is set in Sport mode, there's quite a lot of body lean in bends due to the car's relatively high centre of gravity.
It's not a vehicle that enjoys quick direction changes, then, but there's loads of grip once you've got it settled, and the high-speed ride is impressive if you leave the suspension in Comfort. It's only around town that bumps and potholes start to thump into the cabin.
The Touring drives more like you'd expect a 3 Series to, as long as you order it with the adaptive M Sport suspension (as with the GT, this adds £750 to the price). Experience has shown us that, without it, the body of the car is rather poorly controlled; with it, however, it's superb.
The 3 Series Touring is better than the GT at soaking up bumps at low speed, and is just as comfortable on the motorway. What's more, it has incredible composure in corners, and its steering is both lighter and more precise.
The A5's steering is similarly light, which you'll welcome when you're trying to park. However, it doesn't guide you accurately enough through corners; even Audi's £220 Drive Select system, which lets you play around with the weighting, adds little feedback.
This is a pity because, in other respects, the A5 is pretty good to drive. Its quattro four-wheel drive helps give it a very sure-footed feel, and while it doesn't corner with the agility of the Touring, it does stay flatter than the GT and offers a comfortable ride at all speeds.
Then there's refinement. The A5 is better than both the BMWs at shutting out wind- and road noise, and its engine is smoother when you're trundling around town. This is one area where the Touring is worse than the GT, even though they use the same engine.
All three cars offer a good blend of pace and flexibility, and our GT came with an optional eight-speed automatic gearbox (£1525), which shifts smoothly and always seems to choose the right ratio.
What are the 3 Series GT, A5 Sportback and 3 Series Touring like inside?
All these cars give the driver lots of space and adjustment, but the 3 Series GT offers the best forward view, thanks to its slightly elevated seating position (you sit at roughly the same height as you do in BMW's X1 SUV).
Less attractive is that manual versions of all three have offset pedals, with the A5's particularly bad. You'll be much more comfortable with an automatic.
There are bigger differences between these rivals in the rear. The A5 Sportback is a little short of headroom, but both BMWs are spacious enough to keep a couple of six-footers happy. Legroom is most generous in the 3 Series GT, and it's the only car on test with rear seats that recline.
The GT's boot is also very good – you can fit more luggage under the load cover than you can in either of its rivals.
The Touring does have more space when you load it up to the roof, thanks to its flatter rear screen, which also opens independently, so you don't have to raise the whole tailgate to drop in smaller items. However, the GT compensates with spring-loaded rear seats that can be folded flat from the boot, and both cars have a powered tailgate.
Unsurprisingly, there's nothing between the GT and Touring when it comes to perceived quality. They have identical dashboards that are built from the same high-quality materials.
The A5 Sportback is also pretty classy when judged in isolation, and it's the only car here that gets leather seats as standard. However, some of its switches feel rather lightweight compared with those in the BMWs and newer Audi models.
What will the 3 Series GT, A5 Sportback and 3 Series Touring cost to run?
Most people weighing up these three will be looking at them as potential company cars – in which case the Touring is the cheapest option. It will cost a 40% taxpayer £2372 a year in tax – that's £128 less than the GT and almost £300 less than the A5.
Specify an automatic gearbox – as many buyers will – and the Touring only extends its advantage. The automatic model sits one tax band below the manual. By contrast, the auto version of the GT is taxed the same as the manual, and adding an auto 'box to the A5 pushes it up a band.
The Touring is also considerably cheaper to lease than the Sportback (we didn't have a figure for the GT at the time of writing), and it's easiest on fuel, too. In our True MPG tests, the Touring averaged 56.1mpg, compared with the A5's 48.5mpg and the GT's 47.1mpg. Yes, the GT was an automatic, whereas its rivals were tested as manuals, but the official figures suggest that manual and auto GTs return identical economy.
The GT's comparatively high real-world fuel consumption contributes to it being the most expensive private ownership proposition. Meanwhile, the A5 works out cheapest over three years because it's expected to have stronger resale values than its competitors, and should be cheapest to service and insure.
Which one should I buy?
It would be easy to dismiss the new BMW Gran Turismo as a needless addition to the 3 Series range. However, in reality, it offers definite advantages over the Touring, most notably extra cabin space and versatility.
If you fancy something a little more distinctive than an estate, the GT is certainly worth considering. On the other hand, it still has to settle for second place here, because it will cost you more than the Touring, whether it's a private buy or a company car.
The Touring is also the better choice for dog owners, thanks to its flatter rear screen, while its lower centre of gravity and extra steering precision make it the more enjoyable car to drive.
In fact, the Touring is only really let down by its rather gruff engine and BMW's decision to charge extra for the adaptive M Sport suspension that improves both ride comfort and handling.
Bringing up the rear in this test is the A5 Sportback, although it's far from disgraced. It's arguably the most stylish of the three, and these good looks help give it very strong resale values. It's quieter than both BMWs, too, whether you're dealing with stop-start city traffic or a fast-flowing motorway.
For all its strengths, though, the A5 is starting to show its age. It's more cramped than its rivals, especially in the back, while its cabin feels a little cheap in areas, and the steering is numb. Given that the A5 is also the most expensive to run as a company car, it has to finish third.
By Steve Huntingford