just have to chime in....
IMHO start with things that improve the weapon functionality first. polish the inards, work the trigger group, have it re-tapped for a scope since they tend to strip out easy, fix that auto bolt lever release and so on. search through the web for how to's since most can be done with the most basic of tools and experience. By the time that you get done with all of that you should know the weapon intimately (if you don't already) and should be able to decide what external mods to do if any.
OH!! and welcome to the boards