Group N

In relation to motorsport governed by the FIA, Group N referred to a set of regulations providing 'standard' production vehicles for competition, often referred to as the "Showroom Class".

This contrasted with the Group A all-out competition production-derived vehicles. Group N cars are limited in terms of modifications made from standard specification. Group N was introduced by the FIA in 1982 to replace the outgoing Group 1 as "standard touring cars".

To qualify for homologation, a minimum of 2500 cars of the competing model had to be built in one year, out of 25,000 for the entire range of the model (e.g.: 2500 Subaru Impreza WRX, out of 25,000 Subaru Impreza).

The Group N regulations were officially replaced in 2013. No new cars will be homologated under Group A or Group N regulations, and instead existing cars are reclassified according to Group R rules (specifically the R4 class). The R4 class itself will be gradually phased out.

In 2015, the FIA realigned the rally classes yet again, finalizing the phase-out of R4. A new class, NR4 has been added, and is identical to the previous Group N class, just with a new name to fit in with the other "R" names. R4 cars are now not allowed in FIA sanctioned rallies in Europe, but since R4 was basically a transition group for old Group N, many of those could likely be re-homologated as NR4.

While Group A became the standard category for international touring car racing, Group N found a home as a more economic class in national 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.

The category is still used in circuit racing all over the world, notably in Japan which has the long running Super Taikyu (スーパー耐久, Super Taikyu^?, translated as Super Endurance), as well as in the Italian ETCS endurance series run by Peroni Promotion, but was once again relegated to a secondary status with the introduction of Super 2000, the class of cars currently run in the World Touring Car Championship.

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Wikipedia