I am a bit new on this forum but, have been reviewing good things here. I am considering a little bit here and there on my SA M1A standard on making it a bit more accurate. I thought that I would start with the "NM Op rod spring guide." There are two brands, Badger and Sadlak. Badger is a "drop-in" and Sadlak is not a "drop-in." They both sound good but I like to do things right the first time. So, what would you guys recommend and why?