Both super SUVs, which follow the 2012 and 2013 arrivals of their regular counterparts, arrive to replace the M-powered SUVs that first appeared in 2009.
The new X5 M and X6 M are again powered by a 4.4 litre twin-turbo petrol V8, but power is up now from 414 to 422kW.
Torque gets an even bigger kick, from 685 to 750Nm, but peak torque is now a little further out of reach, creeping up from 1500-5650rpm in the old models to 2200-5000rpm in these new monsters.
Joining the venerable 4.4 V8 for 2015 is an eight-speed Steptronic auto, replacing the six-speed auto of the previous models.
This is matched to BMW’s xDrive all-wheel-drive system, and BMW M promises 0-100km/h times of 4.2 seconds flat in both - a full 0.5 seconds quicker than the old models.
By comparison, Porsche’s Cayenne Turbo, driven by a 4.8 litre V8, offers 382kW, 750Nm and a 4.5 second sprint to 100km/h (4.4 with the Sport Chrono pack).
The big ‘Bimmers’ also best the Mercedes-AMG ML 63 in the numbers department, with the performance Merc listing 386kW, 700Nm and a 4.6 second 0-100km/h time.
Importantly, and in-line with the latest generation of premium Euro offerings, BMW M claims a 20 percent improvement to both fuel consumption and carbon emissions. Both list 11.1 l/100km and 258g/km respectively.
(Those looking for even sharp figures can turn to the 280kW/740Nm M50d models, with fuel use listed at 6.7 l/100km.)
Beneath the BMW M SUVs is a double-wishbone front and self-levelling rear air suspension package, along with three-mode dynamic dampers and large 21-inch alloys wrapped in Michelin Pilot Super Sport UHP rubber.
The usual styling upgrades dominate the exterior of both, with gaping intakes at the front, lightly flared guards through the profile and four pipes at the rear.
Inside there’s a host of M-specific features, including a meaty sports steering wheel with aluminium paddle shifters, sports seats and a M gear shifter.
The new X5 M and X6 M make their overseas debut in the coming weeks. Watch for Australian timing to be confirmed soon.
MORE: BMW X5 M, BMW X6 M