U would want to talk to zspeed and ask them it has a hydraulic piston in it and if that piston is larger than the one in the oem csc then the mastercylinder will have more mechanical advantage to actuate the clutch (the pedal will be softer)
Edit: icydk the zspeed unit is just a saab 9_5 csc with a custom bracket and lines, see they just pull the input shaft seal out.
