Other than names and caliber size differences, what are the fundamental differences between these three AirForce offerings? trigger, loading methods, valve body, etc? For instance if I could get a .25 or .30 in 2 or three models, why one model over another? I do understand the SS, and LSS designations and the CF allows for a higher fill pressure although still unregulated. Also what are good aftermarket changes for the AirForce line that allow a regulator or better operating system?