5" is really really pushing it for stock LCA's. I wouldn't do it. The RE flex arms have waay more flex in the joints than the stockers with rubber bushings do. The stock arms will twist however and so they do ok. They will fatigue and crack eventually if you flex them offroad alot, though. The stock rubber bushings do ride better than most other joints.
When installing my 6.5" lift a couple weeks ago, the LCA's hit their droop limit at 5 or so inches of axle droop. So, running them with no modifications of their stops at 5" of lift all the time would be very bad. They would have basically no downtravel left.
You can clearance their stops if you want. This is done by trimming some metal off the rear lower lip of the shock mount pads, located at the axle end of the front shocks. Look where the LCA would hit the shock mount at full droop. This is where you trim. Just remember that a little trim goes a long way here; don't get carried away. You will also need an adjustable trackbar, or some serious trackbar location at 5" of lift.
I recommend getting the aftermarket LCA's, they should serve you better in the long run and give you a better-performing lift. Also, the RE stuff that I ordered was top notch quality, I recommend them as well. Also, the Deutsch Tech shocks from Rubicon Express are great for me. The ride is nice and the damping is awesome. I would buy them again.
Give Dirk a call at DPGoffroad.com for the Rubicon stuff. He treated me right and his prices are good (surprisingly alot lower than from RE's website). Don't let him talk you into the old man emu shocks.
Good luck, and have fun building.
Jared