I've got the same kit and installed it myself about 9 months ago....it rides much stiffer than stock although I think if I go out and flex it (hopefully going wheeling tomorrow) it will break in nicely. I got 3/4" spacers up front and it sits level at about 4.5" of lift and looks great with 31's with only minimal rubbing at full flex and a little on the LCAs at full lock right or left.
Definately do an SYE/CV as GottaBeJeep says, in fact, listen to everything he says, look through his old posts, he knows it all. I didn't bother with a trackbar, just re-drilled mine and put it on with a new bolt and some oversized washers, tightened the crap out of it too, and will replace when I start having problems with wobbles. I also recently bought some adjustable UCAs to help get the front pinion angle to match the front DS angle, I have some minor vibrations coming from the DS in 4WD because of this...and I want to get it right since I do a lot of highway driving in 4wd during the snowy winters in Colorado.
I'd suggest ordering from dpgoffroad.com, dirk is really nice, helpful, and gets you a good price on everything, I don't know if he is GottaBeJeep or if they are friends or work together, but they are always fast and helpful.