spacers are a good cheap drop. you won't notice any real handing benefits besides the slightly lower stance. you can combine them with the DJM arms if you want if you wanna go hella low later.
XII (formerly Sittin Sic) http://www.xiiperformance.com/
drop springs for the XRunner are a better alternative; it'll get you as low but your truck will handle much better, especially if you combine them with the Bilstien shocks. That does cost more money though.
DJM would be the way to go though if your willing to spend the money. it'll get you to the height you'll want to be at.
4x4 Leafs are a good option to get some low out back. and they're cheap. and personally i prefer the ride of these leafs over stock.
if you do 4x4 leaf swap, your going to want to consider some sort of shock replacement eventually out back to prevent the bottoming out, especially if you combine it with blocks. there are a few options; DJM has rear shocks, OEM XR bilstiens are a bit better than stocks, or you could get QA1s, which are expensive, but probably the best rear shock absorber for this application.
oh, and if you need good, solid, quality custom fit drop blocks, hit up http://www.streetacos.com/
it's all up to you. there are a bunch of different options you just gotta look into them and see how much money you wanna spend, how well you want the truck to handle and how low you want to go.
oh and don't forget replacement bumpstops out back. the energy suspension button style ones fit.