They are easy to install. They use the same screws that hold the liner to the fender, the front one has an optional screw, but all you have to do is drill a small hole through the liner and pop the bolt thru. I want to say the entire install took me 20 min.
Also what I did was cut the factory trim peice to fit with the mudflap. so you cant see the bolts that hold the fender support. All you need is a hack saw (I used a metal blade) and a vice and just cut along the edge, it will pop right back on and sit perfectly against the mudflap - looks very clean and factory.
Ill post pics in a min.. Stay tuned..
Here is the driver's side rear. Note the trim piece I was talking about, the instructions have to throw these away, I just cut em'.

Closer Pic from underneath.
Front - again, note the trim. ** My black truck DOES NOT have wheel to wheel steps**
Far away shots.
Also, I forgot I had a pic from my last truck
WITH wheel to wheel steps to show how the Weathertech's clear the Factory steps. (again note the trim piece)
Hope these help some people with the purchase. I sure wish I had all this info in one place when I bought them. Since it was such a steal for me I just went for it. But I can't say enough about these. They have survived a brutal winter and 2 hot summers with no garage. I will say after the winter its a good idea to take them off and clean them and the fender real well. Since I sold my white truck I had to take them off, and there was a lot of grit behind them that I can see causing issues later if not maintained. I do treat these with Lucas Oil Slickmist Spray wax every time I wash my truck and they are still the same black they were when I bought them - haven't faded.