i have no sunroofs and no factory roof bars... mine has the sd rack that sits closer to the roofline of the truck... but the brackets are the same i believe... it looks like the bracket is the front triangle lookin bit and then to the back of that is bolted a rectangular plate with a 90 degree bend in the bottom that sits in the gutter... so i guess you would mount all the brackets loosely and then possition the rack and line the downtubes of the rack into all eight of the brackets and tighten everthng up... looks like the allen bolt in the bottom of the bracket goes into the vertical supports of the rack which i assume are threaded... sooo to make brackets... piece of pipe with a nut welded into the end welded with two triangular wings on it with a hole drilled in each side, clamping plate for the backside...