Comparing to later model 24 spline shafts (RR/Disco/Defender 90), they are not necked down and the material is harder.
At the moment, 2.5 NA and Detroit locker on 32s, but that will all change.
What I want to hear is who has broken them and in what situations and setup.
I am well aware of the strength limitations of later model shafts and of the various aftermarket brands. What I have not heard of is people breaking these genuine "HD" shafts, so want a feel for their relative strength.