Does anyone know how stiff the power arms are? Stiffer then FSA cranks or Dura ace? Also Is the JIS interface very good. hows the stiffness compared to an ISIS or octalink interface? Also does it squek alot? Thank you.

They are plenty stiff enough compared to FSA carbon pro or Dura ace, if you are buildin a ridiculousy light bike sometimes it is hard to pinpoint stiffness as they seem to respond so much quicker. Word of warning though if you are going for Square taper, then just make sure about the taper of the cranks. I have Storks in Shimano bolt pattern but the taper is iso not jis. I tried it on a jis BB and it does not go far enough

On what BB did you install them?
For the Power Arms Pro you need a 104 mm axle.
And AFAIK at 104 mm the ISO taper is compatible with the JIS taper.
So you can mount JIS cranks on 104 mm ISO BBs and ISO cranks on 104 mm JIS BBs.

Thanks mate

You learn something new everyday

So which bottom bracket and what type of taper should I go with? What do you guys ride? Thanks.