Just a couple of things. First, in order to get the "full monty", you need to buy the entire kit including springs and connector. Either that or purchase an entire tuned trigger assembly. By installing all the lighter springs along with the 3.5 connector you risk getting a lighter strike on the primers, thereby a misfire. If it's for range plinking only, might not be a problem. Prices run around $25-$35 bucks for the kit. Entire tuned assemblies run around $160.

I own a Gen4 19. Tag on the box said a 5.5lb trigger (Yeah, in my dreams). I went to YouTube and using a video there did the ".25cent trigger job". This smoothed things out a bit although it didn't lighten the pull. Next I got a 3.5 Ghost connector from Brownell's for about $10. The pull is now smoother AND lighter....just under 5lb. I can live with that. Many don't trust any connector other than factory, and Glock offers the "-" connector (4.5lb) which will set you back 24.95 plus shipping. Hope this helps.