I have three Rocks (FS-Tac and CS-Tac in .45, .22TCM/9mm); and each has a different recoil spring system. They all seem to work very well and since I have two or three bushing wrenches the take-down procedure difference is moot on the full-sized guns and I have a RPRC (Reverse Plug Retention Clip) for the compact so it is no problem either. Two have polymer MSH's, one has steel; again, no real difference observed in operation and the difference in weight is negligible. So those are two areas of modification I prefer not to do. Triggers are a place where changing can be make a measureable improvement and I have had good luck with Cylinder & Slide units, properly lapped into the bow-channels and adjusted. Sights are another place where I'm not fond of the replica Novak's that come on the guns. I've applied Nitesighters to the appropriate blades and switched the adjustable rear sights from the TCM to the FS-Tac. For the TCM, a machinist friend and I are fabricating a Rock Island-specific mount for a small red dot reflex sight. Grips get changed with regularity while I search for the perfect hold and holsters are beginning to fill a whole shelf in my closet. I'm not a great shot (arthritis and old eyes can do that to you), but I enjoy the sport and am confident that any attacker will not be leaving my presence feeling happy. Rock Island pistols shoot accurately and reliably and that is all one can ask of a 1911 but what sets them truly apart is the quality of their customer service. There simply is no firearms company that matches their attention to making happy owners and keeping them that way.