The Audi quattro concept is a concept car produced by Audi and presented at the Paris Motor Show in 2010.
 It commemorates the 30th anniversary of the original Audi Quattro and the Audi quattro four wheel drive system.
 Based on the Audi RS5, it features a modified 2.5L five-cylinder TFSI engine and the sixth generation of quattro transmission.
 It had been reported that Audi are considering a limited production model (200–500 cars) based on the quattro concept, but the project was shelved in 2012.
The Audi S4 is the high performance variant of Audi's compact executive car A4.
 The original Audi S4, built from 1991 until 1994, was a performance-oriented version of Audi's 100 saloon/sedan.
 All subsequent S4s since 1997 have been based on the Audi A4; and as the A4 has evolved from one generation to the next, so has the S4.
Audi Ur-S4, and Audi Ur-S6 were unofficial names for the original models of the Audi S4 and S6 automobiles.
The Audi V8 ("Typ" 4C) is a four-door, full-size luxury sedan, built by Audi in Germany from 1988 to 1993, as the company's flagship model.
 It was the first car from Audi to use a V8 engine, and also the first Audi to combine a quattro system with an automatic transmission.
 Early cars used 3.6-litre V8s, while later cars featured a 4.2-litre version of the engine.
 The Audi V8 was replaced by the Audi A8 in 1994, although the A8 was not sold in North America until 1997.
The "B5" version of the Volkswagen Passat, based on the Volkswagen Group B5 platform, was launched in 1996 in Europe, 1997 in North America, and March 1998 in Australia.
 Its PL45 platform was shared with the first-generation "Typ 8D" Audi A4, which was unveiled 2 years earlier, and saw a return to the Passat sharing its platform with Audi's equivalent model for the first time since the second-generation (B2) Passat, which shared its platform with the second-generation "Typ 81" Audi 80/Audi 90 (the A4 is the successor to the Audi 80 line).
The Audi Q5 is series of compact luxury crossover SUVs produced by the German luxury car manufacturer Audi from 2008, The original first-generation ("Typ 8R") model was the third member of the "B8" family to be released after the Audi A5 and fourth-generation A4, all being based on the Audi MLB platform.
 The second generation Q5 ("Typ 80A") debuted in 2016 and shares the Audi MLBevo platform with the corresponding "B9" versions of the A4 and A5.
The Audi A4 DTM is a 4-door touring car (DTM) constructed by the German car manufacturer Audi.
 It was first developed for use in the 2004 DTM season, replacing the Audi TT DTM at the end of the 2003 DTM season.
 Based on the Audi A4, it was continually improved over the course of six facelifts between 2004 and 2011.
 The Audi A4 DTM was succeeded by the Audi A5 DTM in 2012.
The Audi S5 is the high-performance variant of Audi's A5.
 It is also the coupé, cabriolet, and five-door fastback versions of the fourth-generation (B8) Audi S4 saloon and estate models.
The Audi 5 Series DTM (also known as the Audi A5 DTM (2012) later Audi RS5 DTM (2013-present)) is a DTM touring car constructed by the German car manufacturer Audi AG.
 It was developed in 2011 and has been raced in DTM seasons 2012-present.
 It was designed by former Audi Head of Research and Development Wolfgang Dürheimer.
 The A5 DTM replaced the retired Audi A4 DTM at the end of the 2011 season and based on the production Audi A5.
The Audi RS4 quattro is the top tier and highest performing version of some specific generations of the Audi A4 range of automobiles.
 It is a sports-focused compact executive car (often called sport compact in some countries ), produced by Audi's high-performance private subsidiary quattro GmbH, in limited numbers, for German car manufacturer AUDI AG, part of the larger Volkswagen Group.
 It slots distinctly above the Audi S4, as the fastest, most sports-focused model based on the A4's "B" automobile platform.
 The RS 4 made a comeback in 2012, in Avant form only based on the Audi A4 Avant.

Question: The Audi RS4 quattro is the top tier and highest performing version of some specific generations of the Audi A4 range of automobiles, it slots distinctly above the Audi S4, the original Audi S4, built from 1991 until which year?
Answer: 1994