Actually Stage 3 is still sprung. There is an option for solid hub I believe and there are 4 and 6 puck options.
For an update, I spoke to Matt at SPEC and the starting thickness is only .310" and I am at .295-.300" so I am still good to go. Since the material the stage 3 is made out of is so high wearing they don't need to make the material as thick as an orgainc clutch.
