BMW 6 Series vs BMW Alpina B7

What's the difference?

This isn't a car for everyone's tastes, but if you fit in to the buyer group that just doesn't really know what they want in a luxury car, it could be the perfect fit for your family. The 6 Series GT is a practical large prestige car, albeit one that will likely find very few buyers.

The BMW Alpina B7 is a special car destined (like all Alpinas) to be a collector's item, due to its rarity and exclusivity. I asked Alpina just how many current model B7s there are in Australia and the answer was "less than five", which is just as mysterious as most people find the car in general.

The B7 is fast – too fast to enjoy legally on Australian roads – but it is also supremely comfortable and well appointed. For Alpina fans lucky enough to be driven in on,e this would make for a truly rare and niche way to be chauffeured.

There is no denying the 6 Series GT looks better than the old 5 Series GT. It isn't as frumpy, it looks more sporty, and to me it appears to have grown into its identity with more conviction than its predecessor.

That said, I don't necessarily like the look very much - it's a bit like a BMW X6 that has been rounded off a little and lowered down substantially. But I can appreciate some of the finer design aesthetics that it offers up: the frameless windows are a nice touch, and the swooping roofline looks smoother than a duck's back.

Other things like the active grille shutters and the air breathers ahead of the front doors are nice functional touches, and to my eye it lives up to BMW's hope of it looking "smooth but muscular". You can get the 630i with either the M Sport package, like you see here, or the more sedate Luxury Line, which is, well, more luxurious looking.

The M Sport styling and equipment package you see in the images here - with M aero kit and 19-inch wheels (ours had been upgraded to optional 20s) - help out with the athletic look of this very big vehicle.

It's huge in fact. The length of the 630i is 5091mm long, it measures 1902mm wide and sits at 1538mm tall, with a lengthy 3070mm wheelbase.

All that equates to a lot of room in the cabin, and what a sumptuous and delightful place it is to be - leather, wood and plush finishes abound.

This is a good place to start because the B7 looks just like the 750Li it's based on, until you see the first tell-tale signs that it's not one.

There's the front wing with Alpina lettering and the boot-top spoiler, the graphics, which run the length of the car, and the 20-spoke wheels with Alpina badging.

This is late '70s, early '80s styling at its best (and possibly worst), but these special cars can pull off the irony-free look because this is how Alpina BMWs have rolled since 1975, when the E21 320-based Alpina A1/3 was launched.

BMW badges have been left on the bonnet and boot, but there's Alpina B7 BiTurbo lettering in place of the 7 Series identifier.

Most people walked by it in the street thinking it was just a big BMW, others scratched their heads wondering what I'd done to my big German limo and a handful almost dropped to their knees in praise and wonderment at spotting a rare beast like this in the wild.

These people all had their own Alpina stories – one was the third generation of an Alpina-owning family. You become a member a small and passionate club when you buy into this rarefied brand.

The standard B7's cabin is close to identical to the luxurious interior of the 750Li, save for Alpina-embossed stitching in the headrests of the soft, leather seats, the virtual instrument cluster and the Alpina plaque on the centre console denoting the build number.

The B7 is long, low and wide at just under 5.3m end to end, 1.5m tall and 1.9m across. A 3.2m wheelbase means cabin room is more than just spacious.

The B7 rolls off the Dingolfing production line in Germany and is then handed over to Alpina's facility in Buckle, where significant changes take place. Read on to find out how the B7 is different from a regular 750Li.

Now, I said before that this is a bit like an X6, but it has heaps better interior space than that SUV.

As soon as you slide into the driver's seat, you feel like your inside a large car. The cabin space is plentiful, and there's an abundance of storage on offer, too: there's a split-lid armrest between the seats, a pair of cupholders, a phone storage nook with wireless charging, and big door pockets with bottle holsters.

In the back you have access to door pockets, a flip-down armrest with cupholders (that middle part of the seat can fold down completely to allow storage of longer items), and there's excellent room on offer. How many seats in the BMW 6 Series GT? Five - like, five full-size seats.

Because the roofline doesn't rake as sharply as a four-door 'coupe', headroom is excellent for adults (even of the 183cm variety, like myself), and legroom and toe room are equally very good. This is bigger in the back than a 5 Series, but maybe not as plush as a 7 Series… so I guess it makes sense numerically for its nomenclature.

Of course you get climate control in the front (and in the rear if you option it), and the materials are excellent. The media screen is tablet-style, proudly displaying 10.25 inches of high-def real estate that is both touch-capacitive and controllable by way of the central rotary controller with touchpad. And get this - you can even use gestures to control certain elements like volume, swiping and changing tracks… but you have to option that.

The fully digital instrument display is bordered by a set of incomplete dial rings, which is just odd. BMW, back yourself - your buyers can handle just having a digital screen in front of them, particularly when it's as good as this one.

This grandiose hatchback's boot is commodious - with the back seats in place it has a huge 610 litres of cargo capacity, which extends to 1800L with the 40/20/40 seats folded down using the quick release levers in the boot area.

There is no spare wheel (the BMW range is fitted with run-flat tyres) but it does have a secondary hidden storage area under the boot floor for hiding items or stowing wet gear, bathers/swimmers or muddy clothes.

For context, the X6 has 580L seats up, 1525L seats down.

The B7 is a five-seater limousine although with the fold-down rear centre armrest which houses the media control panel the back is really set up to carry two.

That 3.2m wheelbase means cabin space is enormous. At 191cm tall I can sit behind my driving position with about 30cm between my knees and the seatback. Those rear doors open wide and the entrance is huge, making entry and exit almost as easy as just walking through a doorway. The air suspension also rises and lowers the B7's ride height for better access.

Storage is excellent, with two cupholders and door pockets for rear passengers, along with the area inside the centre armrest.

Up front, the driver and co-pilot have a deep centre console storage bin with split-opening lid, two cupholders and door pockets.

Luggage space is good, with a 515-litre boot.

The B7 lists for $389,955, while a 750li is about $319,000. At this level, $70K seems like a downright reasonable premium to pay for a faster, more powerful, better handling and comfier version of the 750Li.

In this case you're paying more but getting more, although standard features are close to identical. There's adaptive LED headlights, head-up display, night vision with pedestrian detection, a 10.25-inch touch screen up front and two screens in the second row for TV and other media functions.

There's a reversing camera, sat nav, harman/kardon surround stereo and Apple CarPlay. There's leather upholstery, seat massagers in the front and rear, four-zone climate control, heated and ventilated front and rear seats, front and rear parking sensors, auto tailgate, sunblinds for the rear and rear-side windows and proximity key.

The safety features are listed in the section below, and that list is also impressive.

Rivals to the B7 include the Mercedes-AMG S63, which lists for $375,000, the $331,700 Audi S8 and even the Bentley Flying Spur, which almost matches its price at $389,500.

Under the bonnet of the 630i is a 2.0-litre four-cylinder turbocharged petrol engine, which produces 190kW of power (at 6500rpm) and 400Nm of torque (from 1550-4400rpm). It uses an eight-speed automatic transmission, and is rear-wheel drive.

That may not seem a lot considering the size of this machine, but consider that some of the steamiest four-cylinder hot hatches have nearly the same outputs, and you realise this engine offers up a far-from slouched approach to propulsion.

The 640i xDrive has a 3.0-litre six-cylinder turbocharged engine with 250kW of power and 450Nm of torque. It gets the same eight-speed auto, but as the xDrive naming indicates, it's all-wheel drive.

But this is the one you'd prefer if you want to hit highway speed in a hurry - the 0-100km/h claim is 5.3 seconds, where the 630i takes a full second longer (6.3sec) according to the company.

Alpina takes the 4.4-litre twin turbo V8 from the BMW 750Li and rebuilds the engine by hand. Alpina fits its own turbochargers, air-intake set -up, high-capacity cooling system and Akrapovic quad exhaust. Output is 447kW and 800Nm – an increase of a whopping 117kW and 150Nm over the 750Li's grunt.

It's interesting to note that the V12-powered 760Li has a smidge more power, at 448kW, and the same torque output as the B7.

How fast is the B7? Supercar fast – the B7 has a top speed of 330km/h, which will see it outrun a McLaren 570 and almost keep up with a Ferrari F12. That's quite incredible for a 2.3-tonne limousine with three TVs on board. A 0-100km/h time of 4.2 seconds is also hugely impressive.

In comparison, a 750Li has a 0-100km/h time of a not-too-shabby 4.7 seconds, but the car is electronically limited to 250km/h.

An eight-speed automatic transmission shifts gears smoothly, although a little slowly in Normal mode, while Sport and Sport+ add urgency and harder shifts.

Finally, the B7 is all-wheel drive, and those rear wheels are designed to steer slightly for better cornering performance.

BMW claims fuel use of 7.0 litres per 100 kilometres, and you'll need to use 95RON premium unleaded when you fill up.

On my trip with the car, I saw about 9.0L/100km across mostly high-speed driving - some freeway, some highway, some country back road touring, and quite a bit of corners and city stuff thrown in as well. I think that's pretty respectable.

What wasn't so great was the lack of premium fuel in some of the 'away from civilisation' places on my route home. Keep that in mind if planning your own GT long-distance cruise.

The B7 is probably not the car to own if you're concerned about either fuel prices or emissions, but then the twin-turbo V8 may not be as thirsty as you'd think, with Alpina stating that, after a combination of urban and open-road driving, you should only use 9.6L/100km.

My time in the B7 saw me double that usage but this could have had something to do with me turning off the stop-start system and driving in Sport mode constantly.

I'll put this out there - if you like to drive, there are BMW models for less than this one that will put a much bigger smile on your face. Like, a 440i Gran Coupe, or even just a 330i sedan…

But if you're in BMW's target market - that being older executive buyers who want space and luxury as a priority over thrills at the wheel, you could do a lot worse.

That's because the 6 Series GT lopes along the highway without fuss - the engine easily coping with the demands of overtaking moves, the adjustable drive modes allowing a light steering and wafting suspension feel to wile away the kilometres.

There are 'Comfort' and 'Comfort Plus' modes, but the latter is a bit too spongy and can be boaty feeling. The Comfort setting is made for the highway.

It is actually pretty agile for its dimensions.

If you decide to deviate from the straight sections, you'll be able to explore a little bit of dynamic range, especially when you dial up the 'Sport' mode, which changes the damper settings, steering weight, throttle and transmission response, and even the digital dials in front of the driver to a more aggressive look.

Our car had the 'Integral Active Steering' setting, which is a variable ratio steering system that includes rear steering - that essentially helps make is more turnable in corners at highway speed, and easier to park at lower speeds. It's difficult to say whether the assistance is excellent or not short of driving a car without the tech, but to this tester it was hard to hide the size and weight (1835kg kerb weight) of the vehicle.

That isn't to say it's clumsy or lumbering - it is actually pretty agile for its dimensions, though it makes a lot more sense on long drives and coastal cruises than it does in the narrow and twisty alpine roads of the Snowy Mountains Highway that I tested it on.

There's good grip from the tyres, and strong response from the powertrain - but if it were my money, and I had to have a 6 Series for whatever reason, I'd be looking towards the 640i model, which has a thumping six-cylinder with 250kW/450Nm - certainly an engine that would be more at home in this car. Plus that model comes with AWD.

Who on Earth thinks a BMW 750Li isn't fast enough or comfortable enough, even with all its horsepower, luxurious cabin and technology? Alpina, that's who.

Redevelopment of the 4.4-litre V8 with new turbochargers, a high-capacity cooling system, different air suspension set-up and an exhaust system made by Akrapovic have made this already exceptional car better. Better to drive and better to be driven in.

The ride, even on those 21-inch wheels and low-profile Michelin Pilot Super Sport tyres (255/35 ZR21 on the front and 295/30 ZR 21 on the rear) is incredibly comfortable. I drove it and also had a chance to recline in the back and be chauffeured (by our photographer) and the ride was so composed and refined it was hard to believe I was travelling along some truly awful urban roads with their cracked and pot-holed surfaces.

And it's quiet, too. Which will suit those in the back being transported swiftly from the airport to their next meeting, but if you're after a loud and angry exhaust note then you won't find it in the B7. Sure, from the outside at full throttle the B7 has a menacing growl, but this isn't a BMW M car that will bark and snarl. 
See, while BMW's M division makes brutal, loud, high-performance versions of their regular cars, Alpina makes comfortable, stealthy, high-performance ones.

All-wheel drive provides fantastic traction and ensures that grunt doesn't just tear the tyres off those rims when you sneeze on the throttle.

And while the air-suspension is soft and comfortable, adaptive dampers adjust for when the road goes twisty, providing impressive handling for a heavy and long car.

Really, though, the B7 is built for long, endless stretches of roads, and the acceleration beyond 100km/h is almost as startling as that from 0-100km/h, as it wants to push straight past 200km/h towards that 330km/h top speed.

Which, unless you know a good lawyer or happen to be one, will send you straight to jail. Yes, the B7 is probably too much car for Australian roads. Only on a German autobahn would a B7 be fully at home.

I felt like I was given a Melbourne Cup-winning racehorse for a week but could only ride it in my suburban backyard.

The Alpina B7 comes with all of the BMW 750Li's safety equipment – this includes AEB, lane-keeping assistance and lane-departure warning, blind-spot warning, active cruise control, night vision with object recognition, auto parking and surround view camera.

Along with the suite of airbags, there's traction and stability control and ABS, as you'd expect.

The 750Li and B7 have not been given an ANCAP score.

BMW runs a condition-based servicing plan, which means the car will tell you when it needs servicing. But you can rest assured it won't (theoretically) cost you much, with the brand's 'Service Inclusive' pack. It covers you for basic maintenance as and when required for five years/80,000km. According to BMW, that includes "annual vehicle checks, oil changes, all filters, spark plugs and labour costs for the duration of the package".

BMW offers a three-year/unlimited kilometre warranty plan, and you get the same cover for roadside assistance.

The B7 is covered by BMW's three-year, unlimited-kilometre warranty. Servicing is recommended every 12 months or 15,000km. The B7 is covered by BMW special vehicles servicing plan, which means services are cost-free for the first three years of the car's life.