fiberglass vs. poly urethane

on ebay, i found a "wings west" fiberglass rear bumper already painted red selling for around $160 w/ shipping. is there a real big difference between fiberglass & poly urethane??? i heard fiberglass chips easily & breaks & doesn't bend like poly urethane.
any pros/cons about either one would be appreciated

THANKS

4thgenhb

well with fiberglass you are able to make the kit fit a lot better because it can be manipulated and you can set your own 'glass if you are good. i am not sure tho since i haven't dealt much with kits so i'm not truly sure, that's just what i have heard.

Poly is generally the better product all around, it depends on how many layers on fiberglass is used some use 3 or 5 which is crap, for quality it needs to be about 7 layers. If this is just someone else selling the kit I wouldnt buy it personally, and if it's a business check their feedback and email past buyers.