Most 3" kits use the same-length arms as stock, they are just stronger.
I'm running the stock arms as I didn't have a way to make new bushing inserts for the Rancho arms when I did the install.
I haven't had any problems with the setup.
Although I'd recommend new shocks. The stock ones are crap. Rancho RS5000 are nice and firm, but the RS9000s are worth the money. Especially if you splurge and get the remote controls for them.
Highway use I set them down on 1 both front/rear. Daily driving I set them at 3/1 front/rear as I drive a really twisty road and want the control. 1/1 tends to wallow a bit in hard turns.
5/3 will let you jump the truck and not bottom it out, even with a an extra few hundred pounds up bumper up front. Done it twice. Granted, they weren't high jumps (couple inches off a berm), but they were firm, controlled, landings that weren't harsh at all.
Oh, and side note, I have the dual-shock kit which includes one half-valved RS5000 in the stock location, and one fully valved rs9000 outside of the spring, behind it. That half-valved rs5000 is MUCH stiffer than stock. It was quite nice switching to them when I did the lift.
I put the extra RS9000s in a few weeks later, after putting on the bumper and wanting the extra ride control up front.