Mine are riveted on. One way is to tape them where you want them and then drill from the interior of the car through the body into the scoop. Don't move the scoop between drilling holes. I think mine are held on with 9ish rivets, 3 top, side and bottom. I got a long enough rivet so I could use a washer on the inside of the scoop to back up the rivet so it doesn't pull through the fiberglass. if you do this route don't drill your holes to close to where the mounting flange on the scoop makes it's bend, or you won't be able to get the rivet in. I can try to get a pic tomorrow.