I'm looking to replace my factory bottom metal on my Rem700 PSS SA with the unit from CDI since I have lots of AICS mags from another another 700 project. I would like to know if it is a drop in unit or if there is inletting ( major or minor) to be done. If so, can I do it myself. Heard great things about the unit and would rather not buy another complete AICS. Any and all advice appreciated.