I've seen all the billet inserts. I feel they are way over priced for a little chunk of aluminum. The Iron Glass ones are, well, glass. They had a black glass that was pretty sweet looking. I've conceded to just putting reflectors back in. I spent some time the other night trying to design an led set up to illuminate them. I think it's more trouble than it's worth.
I cut a piece of plastic, painted it black on the under side & stuck a sticker on it. Got a sticker that has "Live to Ride Ride to Live" that some day I will do the same thing to.