Well, I finally got around to reinstalling my rock guards after removing them due to gravel and debris getting trapped in between them. I used the 3M tape method along with the 2 screws, no clips. I cleaned both surfaces thoroughly and wiped them down with an alcohol swab and applied the 3M tape to the vertical portion of the guard. I don't know why I didn't do this from the beginning! IMO, they should ship this way! Forget those clips that can damage your paint and can allow road debris in between. With proper application (surface prep), these rock guards are not going anywhere! And by only using the 3M tape on the vertical portion, the guards can still be unscrewed to let accumulated gravel out.
I am very happy with this new mounting solution!