I am quite happy with the sliders, no rattles or squeaks. They do not go below the frame rails, but I believe there are higher clearance options if that is the most important criteria for you. I have not put the vehicles full weight on them, so I cannot comment on that.
I will be in Moab next week for the 1st time and are looking for somebody that want to do a few trails together. Nothing serious since I will have my family with me. I am thinking Fins 'n Things, Hells Revenge (other ?) if weather permits.
Sorry, I can't help you there. I did not install it myself. My understanding was that they struggled a little with the rear bumper and tire carrier, but the front went smooth.
I have it as well with the sliders and rear bumper. Very happy with the bumper, very solid. It is on a Rubicon though, so it leaves a small gap between the bumper and the fenders. Pictures below.
I finally bit the bullet and got 1-Ups for the roof. Mounted it with quick release bike saddle cam action bolts - Worked really well.
Here are the bolts with a strut nut that fits in the Rhino Rack pioneer platform.
Here is the bottom of the 1-Up roof rack.
Mounted on the platform...
No problems... I originally wanted to add motobilt rock rings which did not fit, so I had to make it myself. Here is the final product. Had it laser cut at sendcutsend.com and painted with rattle cans.