@Klocko
Not exactly on the colors. A mod starting out as green instead of no color will have 1 higher stat at the end than the one that started no color. Blue will have 2 ect.
Yes they change color as you lvl them and a new stat unlocks. But a mod that starts out having that stat will upgrade that stat instead of just unlocking it. Hence why orange, or tier a, is the main mods you want.