The changes were a Wilson Extractor, a trigger job to 2.5 pounds and I replaced the cheap ass plastic "fiber optic" that wasn't. Seriously, they couldn't just buy a piece of fiber optic and use that? Ridiculous.
I bought another piece of fiber optic for replacements for the Smith and Wesson M&P Pro and used that. The channel was metric so I hand drilled to fit the rod. I have replaced six rods by now. It's important to use the heat from a lighter. Do not touch the end with the flame. Let the heat build.
I talked to a guy who said he couldn't see his fiber optic and when I asked his procedure, he said he touches it with a soldering iron. Big mistake. You need a clean round end to collect light. Not a smeared porous, flat end.