Market placement is going to be the challenge for BMW. They certainly have an array of 3.0 liter I6 M motors to choose from. My prediction is that the F97 X3 M will be slightly lighter than the G01 X3 M40i; 4230 for the M40i vs maybe 4000 lbs to 4100 lbs for the X3 M.
The F85 X5 M is 4.1 seconds to 60 MPH and the X3 M40i is 4.6 seconds to 60. I can't see BMW putting out an X3 M that is faster than the X5 M until it is revised so I'm thinking we'll see the X3 M come in at around 4.2 to 4.3 seconds.
BMW Blog claimed twice that the X3 M will get the new S58 motor with 450 to 460 HP in these articlse back in March, 2017:
http://www.bmwblog.com/2017/03/31/ba...2019-bmw-x3-m/
http://www.bmwblog.com/2017/03/13/bm...50-horsepower/
With the M40i at 355 HP and 369 lb-ft torque and the S55 at 425 HP and 406 ft-lb of torque, I think seeing an X3 M with 450 to 460 HP is optimistic.
BMW Blog later revised their estimate in an article from August 29th, dropping it to 425-430 HP; I think this is more realistic.
http://www.bmwblog.com/2017/08/27/up...outh-carolina/
It would not surprise me if the X3 M ended up with the same base S55 motor in the current F8X or a tuned down S58 with a possible Competition Package a year or so later with slightly more HP as the F8x M3/4 and X5/6 M get revised.
Either way, it will be a beast of an SUV. I'll be real interested in seeing what price point it comes out at.