Looks like a Pop-Rivet in there. Nice and neat.
Is that rubber stiff enough so it won't be vibrating as you drive?
I was worried about the floppy factor and I've been looking at using
some real solid 1/8" G-10 (fiberglass) board..
I was also thinking about the angle. Most of these little wheel dams,
seem to be flat to the air flow.
I wonder if it would help if the dam was mounted at an angle?
Allow the air to fall off to one side maybe?
But which side? Outside the tire or under the car?