I have the RK RRD 2.0's and I have to say, the warranty that RK offers is outstanding. I had 2 leaking shocks. I sent them all 4 and they rebuilt them all at no charge. They even changed the end caps with the new updated design. The only gig was I paid for shipping, no big deal. I think the shocks leaked because I didn't have it bump stopped and was basically using the shock for a b/stop.
I will say my jeep rides harsh, not sure if it's the springs or shocks or just the fact that it is a light 2dr when compared to the heavier 4dr. with longer wheel base. ???