modify the ruleset from the FIA standard. By 2013, nearly 20 automobile manufacturers have built or been represented with GT3 machines.

GT3 cars must be based on mass production road car models that are being built and sold at the time of homologation, which does not necessarily include the engine (e.g. the BMW Z4 GT3 used the 4.0L V8 from the BMW M3 E92, while the Mercedes-AMG GT3 the 6.2 V8 from the Mercedes SLS AMG