FYI Both statements are correct. The X5MC has 50% more power than the M2C, and the M2C has 34% less power than the X5MC. Depends on the reference.
I was fortunate to drive the new M3/M4 on the Indy road course at the M events. Most statements are correct, the M2C is definitely more raw, but the M3/M4 are plenty capable and track suited. I did have grossly uneven tire pressures the first session with one tire over 50psi but the second session was good and the M4 was quite good and confidence inspiring. I didn't have a chance to truly test low end torque, which is where the X3M's S58 is a let down, especially as compared to the M2C powerband.
PS: I also drove the M4 GT4 (previous gen) a full session. That car is incredible and easy to drive, perfect balance and behavior as you get rewarded for proper driving style big time.
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2020 X3M non-comp, Alpine White over black : Exec Pkg, ventilated M Sport seats, 20"s
2020 M2 Comp, Sunset Orange/Blk: Orange stitching, DCT, exec pkg, bicolor rims
Gone '18 M550i, '16 X4 M40i, '15 M5, '13 X3 35i, '12 335is, '11 X5 50i, '09 Z4 35i, '08 550i, 06 X3, 06 650i, '02 M5, '99 540i