For my 97b I installed the srs1 and rrk. I?m not building a race gun just wanted to cleanup the trigger pull. Other than the trigger shape the rrk didn?t seem to make much of a difference. The over travel screw made no difference, could have removed it. The take up screw did very little, not the 5mm advertised. The trigger has only one thread for the screw and loctite would not dry and lock it. Had to use medium super glue. The polishing of the internal parts and clipping two coils off the 13lb. hammer spring made the most improvement. Before clipping the hammer spring, it seemed the entire 7.5lb DA pull was at the initial movement of the trigger. I haven?t measured the pull weight after clipping the spring but have run more than 600 rounds without a light strike. Even with cci primers.