I'll watch this with interest. I have used M970 on my Hustler for 2 years now but have a problem, they keep coming loose no matter how much I tighten them. On close examination all the splines are damaged which means I can't get the torque to keep them tight. Now, it's a chicken and egg situation, are the cranks coming loose because the splines are damaged or did I damage the splines because the cranks come loose???
That's my experience of M970 based on 2 years riding. Everything from XC to DH really.
I'm going to replace them ASAP so I'll watch this thread with interest!