Diesel 2000 is an FIA

Fédération Internationale de l'Automobile

The Fédération Internationale de l'Automobile is a non-profit association established as the Association Internationale des Automobile Clubs Reconnus on 20 June 1904 to represent the interests of motoring organisations and motor car users...

 circuit racing classification for modified production based touring cars using turbodiesel engines.

Like its counterpart, Super 2000

Super 2000

Super 2000, also known as S2000, is an FIA specification and classification for production based race cars. The specification is split to cover both rally and touring car racing. Super 2000 rally cars are also permitted to compete in Super 2000 World Rally Championship events...

, the category is open to large-scale series production touring cars modified by a kit. Cars must have at least four seats and at least 2500 fully identical units must be produced within 12 consecutive months to allow homologation. However, unlike Super 2000, Diesel 2000 allows only 4-cylinder turbocharged diesel engines with a maximum capacity of 2000cc.

The category was introduced to the European Touring Car Championship

European Touring Car Championship

The European Touring Car Championship was an international touring car racing series organised by the FIA. It had two incarnations, the first one between 1963 and 1988, and the second between 2000 and 2004...

 for 2004 to allow turbodiesel cars to compete alongside the existing petrol engined Super 2000

Super 2000

Super 2000, also known as S2000, is an FIA specification and classification for production based race cars. The specification is split to cover both rally and touring car racing. Super 2000 rally cars are also permitted to compete in Super 2000 World Rally Championship events...

 vehicles.
When the European Championship was upgraded to become the World Touring Car Championship

World Touring Car Championship

For the video game, known as World Touring Car Championship in Japan, see TOCA World Touring CarsThe FIA World Touring Car Championship is an international Touring Car championship sanctioned by the FIA.-History:...

 in 2005, both Diesel 2000 and Super 2000 cars were eligible to compete for the new title.

Spanish manufacturer SEAT

SEAT

SEAT, S.A. is a Spanish automobile manufacturer founded on May 9, 1950 by the Instituto Nacional de Industria , a state-owned industrial holding company....

 has won the manufacturers award of the World Championship in both and with their Diesel 2000 León TDI

SEAT León

The SEAT León is a small family car built by the Spanish car manufacturer, and Volkswagen Group subsidiary SEAT, S.A. since October 1998.The two León generations are, or have been built upon two differing variants of the Volkswagen Group A platform, and they also share many other components with...

 model. Factory SEAT drivers Yvan Muller

Yvan Muller

Yvan Muller is a French auto racing driver most noted for success in touring car racing. He is a two-time and the reigning World Touring Car Champion.-Single-seaters:...

 and Gabriele Tarquini

Gabriele Tarquini

Gabriele Tarquini is a racing driver from Italy. He participated in 78 Formula One Grands Prix, debuting on May 3, 1987. He scored 1 championship point, and holds the record for the most failed attempts to qualify...

have won the drivers titles with the same model in these two years respectively.