Front spoilers
The best material for these front spoilers is ABS plastic. That is what Mopar Performance used when they made the ones that MAS 100% copied.
ABS will bend back and it is molded in solid black so if you scratch it, it doesn't so very much. Almost 100% of OEM spoilers/deflectors are ABS. That's not by accident.
Fiberglass cracks and alumium will bend (but not bend back).