I have a Kimber .22 conversion kit, and from a simplistic point of view it appears to be the best of all the conversion kits. I was thinking about getting either a Marvel or an Advantage Arms unit because they lock back after the last shot. There aren't any really good videos I could find, but it appears the Kimber is the only one that needs no special tools to install. The Marvel unit has it's own slide stop which is a two piece and once the slide is on you have a special wrench you turn on the guide rod I believe. The Advantage Arms kit also requires a special tool to install. With the Kimber kit you use the slide stop from your pistol and there are no special tools needed. I like things simple, so I believe I will stick with the Kimber and live with it not locking back Wanna kill these ads? We can help!