Get the Apex DCAEK kit. If you want a lighter trigger just skip the install of the sear and trigger springs. I personally prefer the slightly heavier pull that the Apex springs provide. As to the striker block; it is, in my opinion, a total game changer. I have 3 M&Ps; the newest being my 9c. I shot 500 rounds out of it before I installed the Apex parts and I did a short side-by-side comparison. If you hold an Apex fitted gun in one hand and a stock M&P in the other and pull the triggers you totally understand the benefit of the Apex parts. The change to the take-up that Apex USB provides is amazing, and while you could mess around trying to file a better radius onto your stock block, a drop in part that is included in a $90 kit makes a lot more sense to me. It also allows you to put your gun back to stock if the need ever arises. The USB does include a different spring, but I don't think it would noticeably affect pull weight. Another thing to consider with the USB is knocking out that back sight. Having 3 M&P's, I purchased the MGW sight tool. It was another $100 investment, but it makes the job so much easier. I also plan to invest in night sights for my guns so it will come in handy again.