I would suspect the 8.5# H.S., maybe sear spring, FP spring, and reduced weight T.S. + lots of careful polishing/smoothing.
Interesting... I come from the Glock world, so I'm still learning about the spring relationships in CZ 75 SP-01 pistols. 8.5# Hammer spring sounds awfully light to me...
I bought a CZ 75 SP-01 Shadow from Automatic Accuracy (Matthew Mink). It has a 13# hammer spring, 11# recoil spring, and reduced power firing pin spring... Not sure what trigger return spring it has... It is the best USPSA Production Division gun I have ever shot.
Recently purchased a CZ 75 SP-01 in completely stock form. My plan is to turn it into a backup gun for my Shadow, but do all the work myself.
