I have ben using a cheap light from J C Whitney as a third rear brake light. It was stuck onto the paint above the top end of the engine grill. It worked fine and looked ok but the tape had to be replaced every year or so.
I recently removed the luggage rack for a car car show and really like the look without the rack but removing the rack made the 3rd light too prominent and clunky looking.
At one of the many car parts places around here I found LED lights that were on a strip about 5# long that held 5-6 lights. These are easy to mount onto the inside of the metal surround of the grill and are much brighter than what I was using. They are almost invisible until they light up and really improve the appearance of the car. Not only are they bright but they reflect off the strip of metal inboard of the surround and you get double the light!
In the store, all these LEDs are wired up to a switch mounted on the box and a 12v battery inside the box so you can press the switch and see how they look.
The Speedster looks sleeker plus has a lot more brilliance when the brakes are applied. A great find, I thought. I don't guess it was just the new brake lights but I was surprised to get "Best Of Show" at the Nashville, AR show. (It wasn't a huge show though.)