I have one of the $100 rivet nut setters, and the bolt/nut/lockwasher setup that came with the skid worked quite a bit better than it did.
I used rivet nuts to hold on my upper quarter panel armour, and bushwacker flares. I bought two different tools when installing them. One is the rivet gun looking tool, and the other is a ramp type one. So far the bolt/nut/lockwasher has worked better than both of them.
The rivet nuts worked great before I added the stiffeners, I was just having troubles getting them to work with the stiffeners.
As I mentioned before, I am going to sleeve the holes through the frame to keep from crushing the frame rails. I just haven't had time to yet (Winterfest is fast approaching).
I'm tired of drilling holes!