The only way an upgraded shaft is going to do any better is if the material is tougher or there is a better heat reat in the spline transition.
The fracture point is as the base of the splines on the diff gear input shaft - something you can't make bigger on the car as the diff gear cannot be made any larger to accept a larger spline. (Yes I was an axle shaft engineer for 5 years
)
So in conclusion, I hope that the Stage 2's or whatever have a better material and steel microstructure, as well as a higher hardness in the spline region - although going too hard or too deep on the case hardening will make it brittle and prone to fracture all over again.
Heat treating splins is always a bi-atch.
PS - awesome times Greg - my heart would've been coming out of my cheast in excitement if I had out-launched a Vette at the track!
