Most of the Pantera vendors sell a variety of spoilers including replicas of the Gr-3 for the street. Most are fiberglas. If it hangs down more than an inch or so below the chin section of the nose, buy two or three since you WILL crack it in street driving.
I prefer the Revson which matches the body curves and doesn't hang down at all, and still gathers extra air for the radiator. Good for at least 160 mph. Larry at Pantera Parts in NV has both styles of Revson front spoilers.