The factory rock guards look cool and they are painted the body color. They are rolled up on both sides about a 1/4" and have slotted holes in them in two place to allow correct alignment over the rear bumper brace holes. They are a direct bolt-on. I used 1/4" stainless steel carriage bolts, nuts and washers. When installed, they help keep rocks from kicking up between the gap at the bumper and rear cross sill. They are pretty effective and a bit more pleasant than the unsightly looks of the big gap, if they are not there.
Tony