We live on a quarter mile long gravel road. The mudflaps absolutely keep the small rocks from hitting the lower body. The running boards also help with this. They both also keep most mud off the sides of the truck.
I’ll get you some pics tomorrow sometime. These are 265/65/r18 which is basically the same size , 31.5” , that was on the truck in stock form. They clear the front mud flaps easily.
I removed mine but my wife decided she likes it. When I removed it all of the screws were tight. I’ve checked it again when I just changed the oil for the second time and all of them are still tight.
You can drive in a straight line on dry paved roads. You shouldn't turn on dry pavement. You can exercise the 4WD by driving some on gravel or dry roads in a straight line. The 4WD will bind if you turn on dry paved roads. As long as you don't make a hobit of driving on paved roads in 4WD...