I just ordered the exact same ironman kit from ACC that you're about to order. A springs are for a non armored truck, (no bullbar or tire carrier).
I got the B springs which which are very comfy with or with out big bumpers. If you are thinking about getting big bullbars and rear bumper, id get the C spring. And iff you are thinking about big bullbars/rear bumper and ALWAYS having a very very heavy load in the trunk, like 500lbs+, get the D.
Heres a link to the ironman website describing all the spring loads..
http://www.ironman4x4.com/html/leaf_springs.html
And if you do get the ironman lift and don't want to spend a fortune getting someone else to install it, pm me and I can come help, I live close to Marietta. I finished doing mine about 1.5 weeks ago. Super fun haha.
also, if you want to save a little money, I have brand new Ironman front shackles that you can have that I didn't use and are now just sitting around so u won't haw to spend $80 on another set, you'll only have to pay $45 lol.
good luck on your build!!