RE: neubie help
The BDS spring packs aren't bad. You don't have many more options that are going to be big step up.....
Rubicon Express, Skyjacker,....ummm....a set of custom packs?
I don't know of anyone who has reported being unhappy with their RE leaf kit, but I can only speak from second hand experiences. I've installed the RE XJ kits and I can tell you that their quality has gotten much better over the years. I've never had ANY bad experiences from Skyjacker, but reviews I've seen or heard from others are somewhat mixed.
A 4" leaf is going to flex better than a similarly built 6" leaf. The monoleaf SJ kit addresses that, but again, mixed reviews on that one. I'd stick with the 4" if you want to stay SUA, and add Shackle/BL/TJ flares for any extra clearance.