i'll be nice. Urethane is, it is crack proof, and it gives. I have a urethane front bumper on my sunfire, and i bottom out everytime i back out of my drive way. But the bumper just flexes, and goes back to normal, no damage. With fiberglass, it tends to be poorer quality. It is very fragile, but it is very easy to mold and work with. Urethane is also easy to paint. Most of the time you dont even need primer. Mine isnt primmed, just 600 grit wetsand, degreased and cleaned and painted. If you want quality and an easy time with a body kit, get urethane.
