I have the 2.5 flex with the 5100's. It rides better than it did when it was stock. I did some light wheeling with it last weekend (only been on two weeks) and have no complaints. My JKU was stock when I installed it, I forgot to measure before the lift. I got more than than 3" on the front and the 2" on the back. Keep in mind the RK measurements are based on JKUs with lots of accessories.
2012 JKU Sport, Rock Krawler 2.5 Flex, Smittybilt SRC Side Armor, Mesh Grille MOD, Sony Double DIN AV Receiver, Back up Camera, Kicker Speaker Upgrade, ARB Twin Compressor, Dominion Off Road High Lift Mount, Homemade Paracord Grab Handles, Nitto Trail Grapplers, Paramount Rear Bumper with Tire Carrier, KC Hilites Daylighters, under seat lock box, Metal Cloak Front Bumper, BARTACT Seat Covers, BARTACT Sun Shade, x20 Comp Winch, sPOD, ARB Air lockers, 4.10 Gears.