While the new models retain their 4.4-liter, twin-turbocharged V8s, power has increased from 555 horsepower to 567 ponies. Torque is up more significantly, climbing from 500 pound-feet to 553 pound-feet. The extra twist is slightly less accessible, with peak grunt arriving between 2,200 and 5,000 rpm, rather than the earlier model's 1,500 to 5,650. Still, we'll take the ten percent increase in torque as a net win.
The big powertrain switch sees the old X5/6 M's six-speed automatic replaced with an eight-speed Steptronic transmission from BMW M. This new gearbox feeds power to an xDrive all-wheel-drive system that can variably shuffle up to 100 percent of power to either axle. In conjunction with the force-induced thumper under the hood, this powertrain arrangement allows both M models to hit 100 km per hour in just four seconds. That's a mightily impressive stat in a 5,000-plus-pound vehicle.
Yet, the new gearbox and amped up engine make for an even more impressive vehicle at the pumps (not that consumers of 560-horsepower, $100,000, 5,000-pound crossovers care about such things). Carbon dioxide emissions and fuel consumption are down 20 percent on the European cycle.
Keeping all this technology shiny side up is the job of a double-wishbone front suspension and a standard self-leveling rear air suspension, three-mode dynamic dampers and huge, staggered Michelin Pilot Super Sport UHP tires, with 325/30/21s in back and 285/35/21s in front. For the record, those tires dwarf the rubber on proper supercars like the Ferrari 458 Speciale.
Of course, there's more than just oily stuff to distinguish BMW's M cars. The performance division has given both the X5 and X6 significant aesthetic updates to fit their high-performance role. Flared wheel arches, standard 21-inch M wheels, massive intakes in the front fascia and arguably the coolest wing mirrors we've seen on a production car grant the new M models with seriously eye-catching looks. Typical M features, like quad exhausts and side gills are also present
In the cabin, M's new over-large steering wheel has been fitted, complete with aluminum paddle shifters, while more aggressive sport seats with fixed headrests and an M-spec shifter round out the most visible interior changes.
