some teams run 2wd, some run 4wd, many run transfer case's regardless, 2lo is worth it.
as far as i know, there is no sye-kit for 2wd aw4's, but t&j does offer a sye kit for the 2wd ax15, but its prohibitively expensive (can do a 4x4 swap, w/ sye for about the same price). the problem is supply and demand, nobody buys sye kits for 2wd jeeps... so theres no market, no market = no incentive to make/sell the kit.