Urethane vs. Fiberglass (Body/Lip Kits)
Fiberglass or Urethane, the question gets asked all the time and always comes up in threads based on exterior modifcations. I figured I would post up a thread on this since it seems there is always a battle between the two and there are very good reasons why to go with one and not the other. Basically I'll start by explaining some of the differences.
Urethane parts are made of reaction injection molded polyurethane, a material that is lightweight, flexible and resistant to rough weather conditions and everyday road hazards. Because of its flexibility and light weight, parts made out of urethane are usually easier to install. Wings West is an example of a company that manufactures a body kits using high quality urethane. There are several other companies as well, all are very 'reputable' in brand name.
Fiberglass is a material well-known for its resistance and rigidity. It is crucial to choose the highest quality fiberglass for your body kit. Many companies create bad quality parts containing wavy patterns on the fiberglass and unsatisfactory fit. Fiberglass components that are hand laid have no waves and are not brittle or weak. When a part is hand laid, the part will be uniform and will have an even amount of fiberglass throughout the component. Hand laid fiberglass takes the longest, and costs the most but are worth it. Unfortunately I have YET to find out any companies that make good quality fiberglass kits for the focus, and yes this includes JTAutostyle kits which have been 'rumored' to be a decent fiberglass kit. To this day, I don't know of ANY companies that offer high quality hand laid fiberglass kits for the focus, nothing common in North America anyway.
The biggest issues, more common, are below......
Urethane kits are FLEXIBLE so any slight impacts or bumps will not crack the kit.
Urethane kits are RESILIENT to weather so hot or cold, they can withstand the climate (rain, hail, snow).
Urethane kits are EASIER to install since they have some flex to contour to the body parts.
Urethane kits are EASIER to prep before the painting process thus costing you less at the bodyshop.
Fiberglass kits are NOT FLEXIBLE so the slightest bump and she's cracked.
Fiberglass kits are NOT RESILIENT to weather so they can get even damaged even easier due to this.
Fiberglass kits are HARDER to install cause they almost always require cutting, sanding down, etc to actually get the part to fit properly.
Fiberglass kits are MORE EXPENSIVE to prep and paint, due to the needed shop time to get the kit to fit properly.
What it comes down to in the end is you can 'usually' get a high quality URETHANE kit purchased, prepped, painted and installed for LESS then the cost of a fiberglass kit.
Another thing to keep in mind, NO brand name body kit company out there (commonly) uses fiberglass to construct their kits. That should say something if you haven't gotten the point already.
URETHANE > FIBERGLASS