BMW has announced it will release the BMW X3 xDrive35i next year and it will feature the same, 225kW, twin turbo BMW 335i engine. There's now rumours circulating which point towards the production of an 'M' variant, much like the BMW X5M, without the twin-turbo V8.
Although definite plans haven't been confirmed, the BMW X3M is likely to be powered by the same twin-turbo inline six as the upcoming BMW 1 Series M. Sources expect around 240-270kW of power. There's also a spectrum of chassis and suspension upgrades presumably planned for the car as per usual 'M' product philosophy.
Although these are just rumours for the time being, the M model would continue to expand the M Division range and tap into the off-road segment with blistering off-road performance, that is capable on-road too. We'll keep you posted.