I have to correct my post above. I talked to the transmission shop that 5 years ago was adamant about having to harden the input shaft after machining it to fit in an RX7. Turns out they have no idea where to get an input shaft hardened (Ok John I know I am flirting with additional prurient responses, but I guess I will have to take that chance ). Same owner and pretty sure the same guy I talked to originally. So I will assume that no hardening was done or will be required. I will probably test hardening one anyway just to see how much harder it gets.
Then I guess I will change my question to: is it possible to effectively harden the shifter forks using something like Cherry Red Case Hardening? It is my understanding that the case hardening only affects the top 0.020" of thickness. Is that enough to help? I guess the question could also be rephrased as: is that how the shifter forks are being hardened for SM use (I assume they are legal, since they are openly advertised as being used in SM transmissions)? I would like to harden the shifter forks in my endurance RX7.