I run the 4" RC, it was in my budget and works fine for what I use the Jeep for. Flex is fine, though I don't run front or rear trac-bars or sway bars so that helps. Highway ride is about what you could expect from a lifted YJ. Other kits such as the BDS are very nice, but at the time were more than I wanted to spend. I will need to add a SYE with the lift at some point.