Ummm, not they do not go through. You drill out a hole, and it comes with self tapping bolts that fit very snugly, not all the way through the frame.
I have had mine on for 1.5 years,and a lot of wheeling. I have had ZERO problems, excpet that rocky road made them way too long, and I had to cut off 2-3 " to fit 34s. They designed them for 29" factory tires, silly.
My bad! I just assumed they were like all the other bolt on type sliders.
Psst, what real offroader would put larger tires on their rig?