Hello Sam, as I like to say to all our servicemen, thanks for your service to our country...and defending our freedoms.
As to your questions...there are many that could answer your questions with abit more "tech talk and experience" than I but I will start the ball for you...
As for trouble and money, well that all depends on what you want.
I think one of the best is the LaRue Free Float hand guards, cost is around $273 to 329.00 depending on the length.
stores.homestead.com/Laruetactical/Categ...tegory=AR+Handguards
as for the trouble to install it, well that I guess depends on your ability. Oh don't forget that depending on the length, you might have to swap out your gas block...
Being I also have a A4 C, I have put it in the sub MOA at 100 yards and pretty good at 2 and three, being a novice shooter. But being you are planning to go to a SASS upper type down the road I would say save the money and put it into the other upper...This is what I have on mine, a Midwest Industries drop in for the ArmaLite AR-10 A4 C....cost is about 2 bills.
www.midwestindustriesinc.com/index.cfm?f...play&category_id=188
It will take some installing, you have to center your barrel nut but it is well worth it for the Carbine...check out the Articles tab on the top tool bar...for a look.
As for the suppressor, well that is a whole nother topic...
So I hope this has been some help, there are several here that can help you with the things that you want to know.
As for picking our brains, well that sounds messy
but post away with the questions....
BMS