can you put a shimano XTR M980 175mm stage power meter on a XT M785 175mm setup? I would like a stages power meter on my set up but cant figure out if the bottom bracket sizes are correct and if even the new crank will fit at all?
Both the M785 and the M980 are hollowtech II systems and compatible. They use a compatible bottom bracket sm-bb70 and sm-bb93, which are English threaded 68/73mm.

The M980 uses the same clamping system as other Hollowtech II systems which is different to earlier xtr cranksets which required specialist tools.

The stages power meter comes as a replacement crank arm with the meter built in, so while this set up would work for aesthetic purposes wouldn't it be better to get the m785 meter?