Hi Franklin, No pictures. I have a bump on the rear of my rear spoiler per the Volt aerodynmics team results. I do not know if its working. But its something you could do. The volt guys said that a small smooth bump (they show the profile change in the video) at the rear of the rear spoiler improved the drag. The bump I made is only 2 feet long, so there is 6 inches on either side with the stock shape. The glass below the bump stays cleaner. Not sure if that is good or bad. It could be good in that the air flow stays in streamline behind the bump, rather than tumbling. My bump is about 1/4 inch thick, and 3/4s of an inch wide (in the direction of the axis of the car). I did not get a faired-in leading edge shape, like I wanted too however. I was using rigid PVC foam, and the thin end would have been too fragile.
