The B7 is quick - golly-gosh sort of quick. The version we tried was fitted with xDrive four-wheel drive, which manages the power well enough to launch it off the line and on to 62mph in 3.7sec. Annoyingly, BMW doesn’t do a right-hand-drive 750i xDrive for the UK, so all B7s sold here will be rear-wheel drive, and a touch slower as a result - by half a second, to be precise. It's still far from shabby, though.
The engine is surprisingly boosty, with a good second’s delay between the throttle pedal hitting the stop and your head hitting the headrest. This isn’t the problem you might imagine it to be, though. Most of the time, full throttle is unnecessary, thanks to the enormous level of torque that’s accessible even before full boost comes in. So when you are driving it at up to, say, sixth-tenths, it wafts along in an effortless fashion. The sublimely smooth gearchanges and the muffled eight-cylinder note lingering in the background add to the air of tranquillity.
Then, when you give it the beans and the active baffles in the bespoke stainless exhausts open up, the pipes trumpet loud but thoroughly dignified woofles to you and any fortunate passersby. At the same time, the B7 sits back on its haunches and the bonnet rises by a few centimetres. Not in a lairy, intrusive way; it’s more subtle than that, and deeply satisfying. If the forces acting on your body weren’t enough of a pointer, this just reminds you of the prolific speed you are gathering with each passing moment.
Join an autobahn at, let's say, 40mph, and if it’s clear, you’ll see 170mph showing on the Alpina-remodelled digital instruments in a time that feels like it would trouble a superbike. We didn’t test the theory that it’ll crack 205mph, but we don’t doubt for a moment that it would. We can tell you that at silly speeds, Alpina’s attention to aero detail has paid dividends; the B7 feels rock solid.
In Comfort mode, those air-filled balloons supporting you and the car absorb the cragginess of most roads. The only issue is that typical 'crash' you get from air-sprung cars, as the hollow bellows fail to stifle the noise, rather than the actual induced motion, from hitting sharp intrusions. There’s a bit of wind noise past 80mph, but road noise, even with the big 295-width rear tyres running across dimpled surfaces, is never an issue.
Press on through corners and Comfort mode still manages the lean pretty ably. But Sport or even Sport+ are what you need to exploit fully the B7’s remarkable composure. The ride is firm in either of those modes - unnaturally so for a limo - but because of the grip and poise you have, it's quite tolerable; you can only admire the way this two-tonne car switches left to right on a B-road blat. Along with the tauter suspension come sharper manual shifts, operated by signature Alpina steering wheel buttons, rather than paddles. They're so urgent that occasionally, on a full-throttle upshift, you get a mild thwack in the back.
Our only major gripe is the steering. There’s vagueness around the straight-ahead and not enough weight build-up to give you absolute confidence in Comfort mode. Sportier modes dial back the assistance and throw in more feedback, but it’s still not progressive enough; if anything, it becomes too heavy.
What about the cabin? Well, our car wasn’t that much different from a regular long-wheelbase 7 Series. It had the standard BMW interior, you see, and not the optional Alpina trim, with beautiful Lavalina leather stretched tightly over every surface. Regardless, it’s a smart place in which to sit while you play with the gesture controls, or adjust the style and ferocity of the seat massage facility.
If you are a bigwig who's opted for a chauffeur to speed you home from a society ball, the rear is an agreeably palatial place. The art-deco-look main lights on the B-pillars are neat, the surrounding ambient lighting that bathes you is swish and the tablet that controls the various functions is entertaining. Personally, simply watching the outside world whizz by, while swaddled in the lap of luxury, was amusement enough.