I put one (dual spring) in my gen4 G19 & (for me) it made no difference in any way. I replaced the guide rod springs in ANOTHER handgun (a Ruger LC-9) from 16lb to 20lb & from plastic guide rod to SS & it made a HUGE difference. I'm sure it was in changing from 16-20lb springs. I immediately had more control & better grouping, but was ALSO shooting 147gr vs. 115gr... I believe if Glock engineers thought there was s big advantage, they'd use SS. Only my opinion, no true evidence on my behalf. Like so many topics, many will say their experiences have been different than mine...