The only difference between wood, fiberglass, and steel exterior is durability. If you bump a steel door you might dent it where wood or fiberglass wouldn't. Steel is considered the budget door. A fire-rating means 'solid core' so from a security prospective you don't care about the fire rating but you want 'solid core' so you get a fire rated door. -- IF YOU FIND ANY MISTAKES IN MY WORK...Please consider that they are there for a purpose. I try to please everyone and there is always someone looking for mistakes!