Did you know that if you use the VIP check-in service at Dublin Airport you’re likely to be whisked to your jet in the back of a shiny new BMW 7-Series? You had better hope that you’re flying business class if the 7 is one of the long-wheelbase versions, too, as any other airline seat will make you feel like you’ve become victim of the economic downturn, in comparison to the sumptuous surroundings in the back of BMW’s range-topper.

If the car so happens to be the top-of-the-range 750Li model – and your driver is in a hurry – you’ll probably be a little nonplussed by the jet’s acceleration on take-off, too. Despite the nomenclature, this car packs a 4.4-litre V8, though what it lacks in capacity it makes up for with twin turbochargers. A healthy 407hp is at your toe-tips, while an eye-watering 600Nm of torque is available from just 1,750rpm all the way to 4,500rpm. The 0–100km/h sprint time may rival several serious sports cars, but it still only tells half the story: that performance is actually blunted by the car’s significant weight, so the 750Li feels even quicker once you’re on the move.

It’s a pity, then, that the automatic transmission more often than not chooses a lower gear when you flex your right ankle a little, despite there being ample torque available. That happens even in the default settings, with the Dynamic Drive Control set in Normal or Comfort. In either of the Sport modes the transmission drops at least two gears, which certainly makes for a quick getaway, but the resulting V8 roar from under the bonnet (nice as it is) isn’t very becoming for a luxury car. In fact, it’s not a subtle car at all. We love its aggressive styling and proportions, but we doubt that the few people in Ireland with any money left will want to shout about it with a big fat 750Li badge on their bootlid. Only foreign embassy officials need apply, and that’s before we mention the thirst for fuel.

However, the 730d is a different beast. Well, different in that it takes 4.2 litres less fuel to travel 100 kilometres, a parsimony that is reflected in the 192g/km CO2 figure. That means it’s comfortably in Band F for road tax and actually only 2g/km away from Band E. This will be particularly good news for company-car buyers and professional chauffeur-driving firms, where the outgoing 730d was already a firm favourite.

While it’s politically and financially more astute to have a ‘d’ on your luxury car’s rump, there are actually few drawbacks to speak of. The 730d’s six-cylinder turbodiesel’s output might pall in direct comparison to the 750Li’s, but it doesn’t feel wanting in reality, offering up rapid overtaking should you need it and faster acceleration than most luxury-car owners will ever need. It’s delivered in a different manner though, arguably more befitting of this genre of car. Where the 750i’s gearbox likes to seek higher revs, the diesel model just calmly rides along on the torque – it’s a more relaxing experience overall. Naturally, neither of these models is cheap: VIPs only I’m afraid.