Longevity of fiberglass fenders?

[turbo wagon]

Hello all, I was wondering if anyone had experience with fiberglass reproduction fenders on a car that’s driven fairly regularly and over the span of say 5 years. I’ve got a ‘70 Challenger and I’m eager to save some easy weight by going fiberglass but don’t want to cracks in my paint anytime soon. I’m also concerned about the headlight buckets on these cars especially as it seems like an area that would quickly fatigue the fiberglass. Thanks for any opinions and experience in advance!