left to right; thin fiberglass, thick fiberglass, poly urethane
MYTH: Urethane is better than fiberglass
THE TRUTH… There are actually advantages and disadvantages to both materials. Unfortunately, fiberglass has received a bad reputation because of some cheap, low quality parts being sold on the market today. The best way to determine the quality is to look for a guarantee or warranty on the parts. High quality fiberglass parts, like those offered by Kaminari, Bomex, CWest, Greddy, ED, etc. is actually preferable to a performance tuner as it combines the aerodynamic and aesthetic advantages that body kits provide without adding the excessive weight of a urethane kit.
MYTH: Fiberglass kits break easily
THE TRUTH… Fiberglass can be made many different ways and not all fiberglass is equal. This myth was developed from people’s experiences with cheap, low quality fiberglass body kits. There are many high quality fiberglass kits that are very strong. There are many factory auto parts are made of high quality fiberglass.
Fiberglass, regardless of the quality, can crack or break with a strong enough impact. Please note that this same impact would likely damage a factory bumper or metal body part as well. Fiberglass will crack, metal will dent, and urethane will rip – all of which will need to be repaired. (if you plan on crashing your car a lot, you shouldn’t modify your car).
MYTH: Fiberglass kits do not fit well
THE TRUTH… Again, this reputation comes from cheap, low quality parts being sold on the market today. Kaminari, Bomex, CWest, Greddy, AIT Racing, Extreme Dimensions, and Wings West are all guaranteed to have perfect fitment.
MYTH: Thicker fiberglass is better
THE TRUTH… Thickness does not necessarily equal strength. There are many other factors from materials to manufacturing techniques that come into play. High quality Japanese manufacturers, such as Bomex, prefer thin, light weight fiberglass. This thin fiberglass is not fragile or cheap like some low quality no-name-brand kits out there. Some of the cheap low-quality kits are made of thick strong fiberglass. This can be a disadvantage as the overly rigid part is harder to install, especially if the fitment is even slightly off.