Anyone have knowledge/experience about what is available i.e. switching calibers and the different trigger modules? Going from full size to compact or subcompact and back---what pistol do you start with as a base? Could I start with a compact .45 model and buy the kit to switch to subcompact in 9mm or the other way around? Are the available trigger group modules different as to trigger pull or is it standardized to one pull weight? Any info would be greatly appreciated.