Sadly, I can't comment on LS, as I only have owned Kelderman. LS might be a bit stiffer, which could be better loaded, but worse unloaded, I don't know. I will say that these major suspension upgrades are so nice. My kelderman is an auto-level, so I never have to worry about my headlights being aimed too high into oncoming traffic like it was with the regular suspension. I think LS has a similar feature. Highly recommended.
I'm not as wild about the Rancho shocks that came with the full kelderman package, so I'd suggest bilstein or something else. Find a good place to install, as I assume that makes or breaks it (I live about 2 hours from Kelderman's HQ in Iowa, so they did my install directly).