If you really want to wheel, buy a Jeep and spend another 30K on it. I know I did

Actually, all kidding aside, the best way to attach rock sliders is the way Billy described. Mine have a box in the front and use original bolt holes in the rear that have a tab welded to the tube. The best thing about them is the ability to pivot on a rock without damaging the cladding. I think RockLoging here in Salt Lake still has the plans if you are interested, somewhere around 3 bills.

I am running 10.5 x 33 BFG KO’s. You might consider this size as there is not as much issue trying to fit them. The 12.5 wide will cause turning issues unless you backspace a great deal and then you will have to take out more cladding front and rear of the wheel opening. Irregardless a BFH is required in front of the door and a saws all in front.
Todd