I have the drop in kit for my XD 9. The kit comes with 2 sets of springs, one of them being competition springs. I installed the non competition springs and the new trigger, but left the factory striker spring in. The difference was night and day. Lighter pull, crisper break and nowhere near as much travel. Had no malfunctions of any kind through 200 rounds. When I installed the striker spring that came with the kit, I had all light strikes on my reloads. I believe this was because of the hard primers, not the spring itself. The lighter striker spring worked fine with factory loads.