If you're a newbie (like me), I didn't understand all the acronyms & abbreviations on the forums.
I got some answers from members, but more recently I found out what each helmet means through the website below:
http://www.starwarshelmets.com/fan-made-stormtrooper-armor-submenu.htm
Hopefully this will help all the new troopers! I will post my other findings here (I try to read two hours a day on FISD).