The new F15 X5 on which the F85 X5M will be based received an update to the N63TU V8 from the N63 V8 motor so it follows that the X5M model will logically feature a similar engine update to match the other M models in the lineup as the S63 is phased out. The picture of the tachometer below shows the same redline on the car as previously which means it will not rev quite as high as the M5 or M6 (by only a couple hundred revs or so). The main difference here though is that the M models will feature a dual clutch transmission whereas the F15 X5 and the recently revealed F16 X6 do not.
Performance will improve and it needs to as the N63TU under the hood of the X5 xDrive50i has shown stunning acceleration. If BimmerBoost were to estimate performance of the next generation M SUV's they should be on the verge of breaking the 11 second barrier. That would make for the first production 11 second SUV or at least as close as anyone has gotten.
The DCT addition is remarkable for several reasons. The first of which is that there is no all wheel drive turbo car over 5000 pounds in production with a dual clutch transmission. Audi for the lighter RS6/RS7 switched out their dual clutch transmission for an automatic. Mercedes in the E63 and CLS63 4Matic models also uses an automatic transmission. The heaviest all wheel drive twin turbo V8 dual clutch car in production is the Porsche Panamera.
If BMW feels confident enough to equip 5000+ pound SUV's with this transmission along with raising the output they must have beefed the transmission up considerably. This bodes well for M5 and M6 modification as they of course use the same S63TU V8 and likely a very similar DCT transmission unit.