Well it certainly sounds like your Rough Country kit is living up to it's name...
RC's shocks are nothing to write home about (especially the generic white twin-tube ones), however I know their springs are real stiff too. You may be looking at having to replace both the shocks and the springs if you are to tame it's stiff ride (this is one big reason why the Rough Country kits are not the highest-regarded around here).
I run Fox 2.0 reservoir shocks on mine, though there are many other good shocks out there at different price points too. Unless you plan to romp on it, you probably don't need reservoirs, just something decent. King, Fox, Bilstein, KYB and Gabriel all have some good offerings (I've personally used Fox, Bilstein and KYB). King, Fox, and some Bilstein shocks are also rebuildable/revalvable, so you can tune them firmer or softer if needed.
As for springs, I would suggest you read up on the XJ coil swap if you haven't already and are thinking of going that route, as they are not something you can just stick in there and have work properly. For one thing, it is absolutely imperative that the angle of your steering linkage be correct, otherwise the springs will quickly make light of it in the form of very poor handling (you will need something other than a run-of-the-mill drop pitman arm for your 4" lift). Also some modification to your spring buckets will be needed.
If you are looking for better offroad performance (more articulation), XJ coils will certainly be a big improvement. If your rig spends most of it's time on the street though, then it might be easier to just stick with regular TTB coils. Skyjacker's #134 4" lift coils I recall are about 10% softer than RC's coils, not a huge difference, but may still be enough to notice.