Ask p@55w0rd how well that mounting system worked for him. He has the pics to show what happened.

In all honesty they can take a light hit and sliding, but the crud I throw and have thrown at them on the last trip would have wadded them right into the fender and bent the snot out of the rocker mounting area. Huey's grandson took a pic of my sliders suspending my truck off the ground when I ran it fender high between 2 boulders on Chinaman Gulch. I wouldn't have done it with any that mount to the top of the rocker panel.

Just my .02, but I like the way mine and Knappster's mount.