I've managed some time to come back and update my core mods. They now come in the form of packaged game pcc files. You use them to replace the original game pcc files and then update your game and DLC pcconsoletoc.bin files with ME3Explorer. Instructions in each package.
I'm starting on a mod intended to bring some ME1 armors into ME3, replacing one of the ME3 armors with that of ME1. This particular image is of "Colossus Medium Armor" from ME1. The beauty is that it would be trivial to change to any of the other human armors for import because the ONLY difference between armors in a given class in ME1 is the texture applied to it. Otherwise they are all identical.