History

The GT3 category was initially created in 2005 by the SRO Group as a third rung in the ladder of grand touring motorsport, below the Group GT1 and Group GT2 categories which were utilized in the SRO's FIA GT Championship, and launched its own series in 2006 called the FIA GT3 European Championship. Since then, Group GT3 has expanded to become the de facto category for many national and international grand touring series, although some series modify the ruleset from the FIA standard. By 2013, nearly 20 automobile manufacturers have built or been represented with GT3 machines. Source: Wikipedia

Motivations Bethind the Class

The concept behind Group GT3 was introduced by Stéphane Ratel, head of the SRO Group and promoter of the FIA GT Championship in 2005. The Group GT1 and Group GT2 cars in the FIA GT Championship required manufacturers to build a car based on regulations, and then develop that car to increase its performance, thus increasing the cost for the manufacturers and the customers wanting to race the cars. GT3 was envisioned as a category that would simplify the process by combining several existing cars from one-make series, such as the Porsche Supercup or Ferrari Challenge, as well as other race cars available from manufacturers that did not fit in GT1 or GT2, such as the Aston Martin DBRS9 or Dodge Viper Competition Coupe, and allow them to all compete on a level playing field through strict control of their performance by the FIA. This would allow drivers a bridge between smaller national series and the professional international FIA GT Championship. Further, the category was conceived to use sprint formats for races, but manufacturers could develop and sell an upgrade kit for their cars to allow GT3 cars to be used in endurance races.

Regulations and homolgated cars for Group GT3 were ready by the start of the 2006 season. Eight manufacturers produced cars for a performance and balancing test prior to the FIA GT3 European Championship. Soon after, the British, Spanish, and Italian GT championships added a class for GT3 racing. The class became an instant hit, and continues to be one of the most popular forms of racing to this day. Source: Wikipedia