More 904 Q's

Been reading mopowers thread on "which shift kit" and sounds like what I will be doing , rear servo and accumulater etc . Still need to understand kick down lever and benefits to upgrade??? I am also assuming that 2nd fade out would just be clutch packs that will be replace anyways ? I have also read about leaving one of the five balls out for firmer 2nd shifts, is this redundant with shift kit install?? Sorry man ,first time tranny guy?