Just what's involved in installing an SSS Competition trigger on an Accutrigger Model 12? The sites that sell them are saying they're a simple drop-in, but one user review I've seen says something about it being necessary to modify the trigger bracket (I think that's the term he used) on models with the Accutrigger. No specifics. What's the deal? Is whatever this is easily done with ordinary tools? Are clear instructions provided? I don't even know what a "trigger bracket" is. ???