Looking to upgrade my SA MilSpec. Beavertail - Smith & Alexander or Wilson Drop-in. Would have to alter frame to fit the S&A. Not sure I want to do that with a lifetime warranty. Have seen pics of MilSpecs with Wilson for government models - large gap between frame and safety. I have seen 1 pic with the Wilson commander style on MilSpec, much smaller gap. Has anyone tried the commander drop-in? Would you modify gun with lifetime warranty? Mainspring Housing - changing from arched to flat. If I go from Springfield w/ ILS to non-ILS will I need to change internals? Has anyone used the Smith & Alexander?