Logic has left the building. Or at least it will do when someone walks into their dealer and places an order for the new X5 4.8iS. Nobody needs this pumped-up caricature of an already brilliant 4x4. It’s a study in pointless extravagance and, at £58,025, costs £20k more than the pick of the range, the 3.0d Sport.
Even if you are hell-bent on a V8, you’d struggle hard to convince us that the 4.4 Sport and the resulting five-figure sum you’d have in your back pocket from choosing it over the iS wasn’t all you’d ever need. The 4.6iS sold in tiny numbers, and the 4.8iS is likely to sell in similar amounts. So what is it about this car that’s so appealing?
Posture. The 4.8iS works brilliantly, like the 4.6iS before it. They hunker down on gigantic rims and exhale through funnel-sized exhaust pipes; tweaked X5s with enough bad attitude to send Mr T scurrying back to his GMC van with his gold chains between his legs. It’s an American influence: no longer is it enough to have a great car. To gain respect on the street, lilies need gilding, so BMW has reached for the gold-plate machine.
Doubtless the Germans could come up with some figures proving that the iS’s various body addenda, including the comical rear diffuser, add crucial stability to the X5 at autobahn speeds, but the effect on the high street is less certain. The 20-inch wheels are so wide the thing appears to roll along on four beer barrels.
All X5s look tougher up front following the recent restyle, when they gained a recontoured bonnet and more aggressive grille, but the iS adds further menace with a reshaped front valance. There are two iS-only paint treatments: this Imola red and Le Mans blue, as seen on M3s everywhere, and two chromed rectangular exhaust tips poking into the face of following traffic. But if you want the showy aluminium running boards, or the swivelling headlights, your bill will get bigger.
There’s more to the most expensive X5 than simple cosmetics, however. The success of Porsche’s rapid Cayenne Turbo has proved that there is a small but affluent band of people willing to pay a large premium to sit high and travel very quickly. And in the absence of a proper M-power version, this is as hot a factory-produced X5 as you’ll get. M-badge or not, the figures don’t put it far off.
When BMW breathed on the 4.4-litre V8 at the time of last year’s facelift, power jumped from 286bhp to 320bhp, turning the standard car into quite a hotrod in the process. The 340bhp of the 4.6 wasn’t going to cut it this time around.
Stretching the excellent alloy V8 to 4.8 litres has provided the answer, endowing the iS with near-M5 levels of grunt: 380bhp at 6200rpm and 369lb ft at 3600rpm. BMW’s figures say 62mph arrives in just 6.1sec, which almost certainly means high fives to our 60mph yardstick – blistering pace by any standards, but quite ridiculous in something that weighs over two tonnes and is tall enough to let you lord it over van drivers.
That lofty driving position conspires with the sublime auto ’box, which slurs effortlessly between its six ratios, to rob you of some of the sensation of speed. And while it will eventually nudge 153mph, the cliff-like Cd factor means the rate of thrust isn’t quite so staggering beyond three figures. But few cars are likely to cause much of a problem to this X5 on the road. And with that angry snout looming in the mirrors, they’re likely to move over quick-smart anyway.