body kit question?

i was wondering how much better the material of urethane is compared to fiberglass? I bought a blitz fiber glass body kit for my car and it doesnt fit worth shit. Also the fiber glass isnt as strong as i thought and i can tell its going to crack and chip very easy. My question is should i take my fiber glass body kit to a body shop and pay to have them fit it right or should i just buy a urethane kit? How much better quality are they over fiberglass. I was very disapointed with the quality of the fiberglass and im not sure if its going to be worth it to get fitted to my car and painted if down the road a rocks gonna hit it and chip half it off?
thanks for the help and input

Urethane is so much better than fiberglass. Urethane is gonna be more like the material of a stock bumper... I say go with that instead especially if you already know the fiberglass isn't gonna fit right.