A body kit is a collection of exterior modifications to a car, typically composed of front and rear bumpers, side skirts, spoilers, paint jobs, and sometimes front and rear side guards and roof scoops. These body kits are designed to mimic the look of a racing car without the need for the functionality they provide, such as down-force and weight savings. Street driven cars do not need additional down-force to be safely driven, so items such as large rear wings or pronounced front bumpers (known as splitters) serve aesthetic purposes. There are many companies that offer alternatives to the original factory appearance of the vehicle. Body kits components are designed to complement each other and work together as a complete design. Despite this, the 'mix and match' approach is often seen on cars, where the front of one body kit will be matched with the rear of another, for example. Automotive body kits are usually constructed of either fiberglass, polyurethane, applications (automative parts), or in some cases carbon fiber. Fiberglass is cheap and widely available, although it can crack upon impact. Polyurethane is popular because it is flexible and thus more resistant to damage. Carbon fiber body kits are rare, due to the cost of the materials, and are rarely seen on street-legal vehicles. Further details found below: Fiberglass (FRP) composite is very light and is extremely strong according to its weight/strength ratio. FRP material is easier to fix, if necessary. Polyurethane (PU) is popularized in the manufacturing of some of the highest quality aerodynamic components/body kits for varying automobiles (car, truck, and SUV) on the market. These components include bumpers, side skirts, roll pans, and wiper cowls. Polyurethane allows production of durable components unlike the conventional fiberglass (FRP) that can easily break upon impact. Polyurethane is highly flexible therefore more resistant to damage. Including durability, these body kits when produced by a reputable manufacturer, exhibits less imperfections, are easy to install and maintain, and are affordable. Super-Polyurethane (SPU) is a much stronger- weather proof polyurethane material researched and developed and used exclusively by Japan Tokyo and Japan USA, Co. When fiberglass body kits begin to show cracks, chips from usual wear and tear, a well manufactured polyurethane component have similar durability to a factory installed bumper. As mentioned above, when produced by a reputable manufacturer, tend to have less pinholes and casting imperfections. Flexibility of polyurethane makes them easy to work with. Installation can be completed individually as a ""do-it-yourself"" project, or can be done by a professional. Maintenance is minimal on many body kits. Pricing varies by manufacturer, but is kept in an affordable range. Although they have many good traits, polyurethane body kits to have their downfalls. Fiberglass or carbon fiber components are lighter in weight than most polyurethane kits. Polyurethane again is flexible but more material and thickness is most often needed to keep adequate stiffness for road use. For drivers seeking speed for a high performance vehicle, this can become a problem. Also, unlike fiberglass, polyurethane cannot be patched or repaired. Though it is much harder to damage, if damage did occur, the entire component must be removed and replaced. All consumers must be aware of lower quality replicas on the market. Factory-fitted body kits are now becoming more common, perhaps in response to the growth of the aftermarket tuning industry in the late 1990s and onwards. Many manufacturers now work in-house with their motor sport divisions to develop styling upgrades.