compromise the integrity (physical not moral) of the gears by cryoing them. I doubt it, but I'd double check. The have a very specific tempering process you don't want to interfere with. The engineer at Richmond that designed the gears is Stu Hamilton, nice guy and could give you a yey or nay on the process. His # is 800 476-5638. Great idea on the output shafts. They are the definate weak point of our rear ends (our cars' rear ends, I don't know about yours' personally). I would also look into having the shafts (air craft quality) shot peened. My understanding is that it will help the shear strength some (point at which the part breaks due to excessive force), but will greatly enhance the life of the part (It will take longer to fatigue). That's my story and I'm sticking to it, Mark