These days the idea of ultra-powerful SUVs seems less outlandish than it once did, the car manufacturers mastering the art of enabling to corner at speeds that their bulk, height and unhelpfully high centre of gravity suggest would be unachievable. But this pair, and plenty of sporty SUVs since BMW’s own, pioneering 1998 X5, are capable of physics defying athleticism in twists, if with the help of protecting electronics.
The all-new 3.0-litre twin-turbo is the source of this prodigious power. This is a heartland engine for BMW’s Motorsport division, and among other innovations includes a cylinder head that’s largely 3D printed to produce super-accurate combustion chambers and water jacket passages that would be unachievable using conventional machining and casting methods.
The engine directs its substantial 600Nm (443lb ft) of torque to an eight-speed torque converter transmission and all four wheels, the back axle’s electronic differential usually receiving most of the torque to encourage the car towards defter, rear-drive handling habits.
The X3 and X4 Ms are mechanically identical, the recipe including bigger brakes, adjustable dampers, a (very) firmed ride and quicker steering compared to the X3/X4 M40i. Big wheels, huge air intakes in the front bumper, body colour wheelarch extensions are these cars’ visual signatures, their cabins sportified with racier seats, carbon fibre décor and a pair of small aluminium toggles lodged atop the steering wheel boss (intriguingly, these are labelled M1 and M2, each allowing individually configured settings from the eco, comfort, sport and sport plus algorithm sets controlling suspension, transmission, engine and steering responses, and the speed with which the transmission picks gears). With familiarity this choice will be satisfying for the keen drivers at which these cars are aimed, familiarisation also needed with a gearlever knob whose layout is decidedly obtuse.
You may well use richer adjectives to describe these M models’ approach to the lumps, bumps and fissures of roads in need of maintenance, the optional 21-inch wheels of the Competition versions of these cars thumping, clumping and flunking their way over these disturbances as if their tyres were made of solid rubber, an intrusion that no electronic setting can balm away. The slightly taller sidewalls of the standard 20-inch rims may provide some relief.
Still, these cars can carry themselves around a track at a thunderous pace despite their heft. These M models are remarkable for their ability to contain the effects of their unhelpful physics, those big wheels, the electronic diff, all-wheel-drive, firm springing, super-firm damping and a self-preservationist ESP system combining very effectively to keep you off the grass. Impressively durable brakes help too.
Once the tyres get hot the ESP spends a lot of time choking the engine to prevent slides, adventures towards its 7,200rpm limit achievable only on straights, while high-speed S-bends can provoke a tail-end squirm that may well get you backing off a bit. A lower-slung, lighter BMW M2 would be more composed, and more entertaining as a result.
You’ll be very unlikely to find much of this out on the open road, the mix of prodigious roadholding and law-smashing performance ensuring that. But on the right road, either of these machines is pretty exhilarating, not least for the engine’s suitably combustive soundtrack in sport. You also get the fundamental convenience and practicality of the standard X3 and X4, though the latter is less commodious with its sloping roofline.
Neither car is cheap, but if you have the budget a more off-putting deterrent will be the wincing ride quality of this pair, which is nowhere near good enough for Britain’s turbulent roads. Despite the excellence of that new engine, it makes them hard to recommend.
Stat attack: BMW X3 M Competition
Powertrain: 3.0-litre twin-turbo six-cylinder petrol