The gasket around the lights is soft rubber "u-channel" which fit the thickness of the fiberglass perfectly. It's body shop trim not specifically designed for this application, but it worked like a charm. We just cut enough to fill the circle completely, putting the seam at the bottom (less visible there).
Each light is attached to a custom-bent L-bracket which is welded to the bumper support. We shaped the brackets by hand to hold the light perfectly in the holes. The lights themselves are adjustable, but only slightly up-and-down and side-to-side.
If it sounds complicated, it really wasn't. The hardest part was marking exactly where to cut the holes in the front of the car. Oh, and having someone take a hole saw to your brand new Speedster was kinda fun, too...I couldn't watch!
