For me, i ran into some install issues where I had to cut/grind a few more spots of the frame for clearance that weren't called out in the directions... which was a bit of a pain in the ass because there was no way of knowing this until i had everything installed.
One other thing that I ran into is with the sway bar mount on the drivers side. The holes for the mount are drilled and tapped right underneath one of the supports for the a-arm. So when you go to reinstall the sway bar mount the bolt is too long and hits the support and you can't tighten it down all the way... of course I figured out this problem AFTER I stripped the threads in the A-arm. It's also a bitch to find a shorter replacement bolt to make this work because the head of the bolt has to be quite a bit smaller than most anything you'd find at a local hardware/auto parts store. Even now, my front sway bar clunks when I turn or even put the truck in D.
The weird thing is that I didn't have this issue on the passenger side and if the A-arms are exactly the same just mirrored, I don't know why I would've had this issue. I haven't seen anyone else post a similar problem, unless i got a fluke A-arm that wasn't made right.
Apparently ALL of the kits have their flaws... you just have to pick which ones you're willing to deal with.