The horsehoes started as a Gulf promotion for their version of premium gasoline, which was called "No-Nox". You could get a set of thin plastic horseshoes which I think came in a plastic wrapper, at Gulf Oil stations. They had some glue on them that stuck them to the car. (this goes back about forty years so bear with me if it is a litte fuzzy)
Someone at Gulf decided to put them on the racecars, at least they were on the Fords. I don't recall seeing them on the Gulf Porsche team cars.....but maybe they didn't have as good a sense of humor.
There are very few decals or stickers I would put on a street car...but I might consider the horseshoes. Along with a "Kennedy/Johnson" bumper sticker...except GT40s don't have bumpers, do they... /ubbthreads/images/graemlins/confused.gif /ubbthreads/images/graemlins/blush.gif