I have put Lone Wolf barrels in all of my Glocks and like them a lot. I also replace my triggers with all aluminum assemblys. I put an enlarged mag release on of some sort because they make changing mags much easier. I have Tru-Glo TFOS on a G-22 and they are neat. But a little bulky. I have Trijicons on all of my other Glocks. You might want to avoid the different colors on Trijicons. The yellow ones are less bright and they tend to lose their luminosity a lot quicker. Stay with green/green. I don't care for titanium guide rods, but that's a personal choice. Buy yourself a Glock rear sight pusher because it will pay for itself over the life of your Glocks. Buy an orange plastic slide plate. They're cut a little higher on the bottom so that you can work on your action and then trip the striker to get the gun back down for more work. I have done enough actions that I have developed a really smooth trigger with a 5# tactical connector. You can do as you wish but I feel that a 3.5# connector is ONLY good for range use. I never put one that light on a carry gun. In .357s I have a new G-32 with a spare .40 barrel. I also have a G-27 which has another .357 barrel with two other .40 barrels for it. Check online or on Lone Wolf and get a GOOD CD or VHS on Glock disassembly/reassembly. It will be your go-to for a while until your brain learns the Glocks. I first handled a G-17 in 1980 and hated it. A few years later a friend handed me one and it just "clicked" for me. They build good guns. 
