In relation to international motorsport governed by the FIA, Group N refers to regulations providing 'standard' large scale series production vehicles for competition. They are limited in terms of modifications permitted to the standard specification by the manufacturer making them a cost effective method of production vehicle motorsport. Often referred to as the "showroom class", Group N contrasts with Group A which has greater freedom to modify and tune the cars to be more suitable to racing. Both Groups may have the same or similar models homologated by a manufacturer. Group N was introduced by the FIA in 1982 to replace the outgoing Group 1 as "standard touring cars". At this time there weren't specific formula for production racing cars in competition. The World Rally Championship (WRC) for example only permitted Groups A, B and N cars to compete (Group B was banned from 1987). It wasn't until 1997 that the World Rally Car formula was introduced and other specific formula were introduced in later years. Both Groups N and A, and the details of their differences are described in the FIAs International Sporting Code and several of its Appendices J articles. To qualify for homologation a minimum of 2500 cars of the competing model has to be produced in the 12 months prior to homologation. The homologation period runs for 7 years after every consecutive year of qualifying production of the model, with production of the model considered stopped when less than 10% (250) are made in one year. Before 1993 the production requirement was 5000. Despite having few, if any, modifications, Group N cars are considered a completely different category from stock cars, due the latter generally using purpose-built engines, chassis, and bodies. Circuit racing Touring Cars While Group A became the standard category for international level touring car racing, Group N found a home as a more economic class in national level touring car racing. In many countries, there would often be two touring car championships, one for Group A and one for Group N. The category had some brief success with the demise of the Supertouring class in the late 1990s, when a few national regulations were relaxed to allow a greater number of modifications, in the guise of Super Production. Endurance racing The category is still used in circuit racing all over the world, notably in Japan which has the long running , as well