GT Spirit 1:18 2020 Audi A4 RS4 ABT Avant: City of Berlin Police / Polizei

The Audi RS 4 is the high-performance variant of the Audi A4 range produced by Audi Sport GmbH for AUDI AG, a division of the Volkswagen Group. It slots distinctly above the Audi S4 as the fastest, most sports-focused car based on the A4's "B" automobile platform. The RS 4 made a return in 2012 in Avant form, based on the A4 Avant.

The original B5 version was produced only as an Avant, Audi's name for an estate car/station wagon. The second version, the B7, was released initially as a four-door five-seat saloon/sedan, with the Avant following a short while later. A two-door four-seat Cabriolet version was subsequently added. Their internal combustion engines are longitudinal and located at the front.

The "RS" initials are taken from the German: RennSport—literally translated as "racing sport", and is the Audi marque's highest trim level, positioned above the "S" model specification of Audi's regular model line-up. Like all Audi "RS" cars, the RS 4 pioneers some of Audi's latest advanced technology. It is only available with Audi's Torsen-based "trademark" quattro permanent four-wheel drive system.

Abt Sportsline is a motor racing and auto tuning company based in Kempten im Allgäu, Germany. ABT mainly deals with Audi and the related primary Volkswagen Group brands—Volkswagen, Škoda, and SEAT—modifying them by using sports-type suspensions, engine power upgrades, lightweight wheels, aerodynamic components and more. It has been active in DTM for more than a decade. After the death of their father Johann in 2003, the company with 170 employees in their headquarters in Kempten was run by the brothers Hans-Jürgen Abt (born 1962, Managing Director) and Christian Abt. Since 2011, Hans-Jürgen Abt has run the company.

Starting in 2014, they run a team under the Audi Sport banner in the FIA Formula E Championship for drivers Lucas di Grassi and Daniel Abt. At the 2014 Beijing ePrix, di Grassi became the first driver to win an open-wheel motorsport race in an all-electric car. Ultimately, the team finished third in the first teams' championship

Johann Abt (20 December 1935 – 11 October 2003), who continued a horseshoeing tradition of his family with motor cars, was a motorcycling and hillclimbing racer for the Abarth factory team until 1970. He is the father of Hans-Jürgen Abt and Christian Abt. He later entered cars with his own team, winning the "Trophée de l'Avenir" and many other series. Johann Abt's father founded the first Abt company in 1896.

In 1991 Abt Sportsline GmbH was founded following "Auto-Abt". The headquarters moved to Daimlerstrasse in Kempten-Leubas and first offered about 3,500 square metres (38,000 sq ft) of space. In October 2002 an extension building was opened offering about 3,000 square metres (32,000 sq ft) extra of work space. Since November 2013 there is a third building giving the Abt Motorsports Department a new home.

In summer of 2011 Abt celebrated their 115th anniversary since the first formation of the company in 1896. About 170 employees are working in the company's headquarters in Kempten, Germany, the products are sold in more than 50 countries worldwide. Since 2011 the Abt Lifestyle GmbH, run by Daniel Abt, organizes events for private or business customers.