The latest Audi RS 4 pays homage to the past in many ways. The first RS-branded model from Audi was also a mid-sized model, available only as an Avant wagon.
The RS2 was launched in 1994 as a collaboration between Audi and Porsche. It boasted a 2.2-litre five-cylinder turbo engine making 232kW and could hit 100km/h in 4.8s. Right-hand drive examples are now rare; fewer than 200 were built.
It took five years for Audi to create a successor and establish RS as a brand. The first RS 4 was launched in 2000 and featured a 2.7-litre twin-turbo engine.
Like the RS 2, it was available only as an Avant.
When the RS 4 finished in 2001, Audi extended the RS range to the A6, in sedan and Avant body styles, with a 4.2-litre V8 engine. In 2006 came the second-generation RS 4, also in sedan and Avant, with a new direct-injection 4.2-litre V8 powerplant. Many consider this to be the best RS, thanks to incisive steering and a responsive chassis.
In 2008 Audi switched back to an RS 6 - this time with a monster 5-litre V10 engine derived from its Lamborghini subsidiary.
Until then, Audi had a policy of only producing one RS model at a time, in strictly limited runs. This changed in 2009 with the five-cylinder TT RS, launched while the RS 6 was still on sale.
The family now has four models: RS 3, RS 4, RS 5 and TT RS. It will be five with a new RS 6 next year.
Audi's RS brand doesn't quite have the history of BMW M or Mercedes-Benz AMG (both date back four decades), but it has grown at an astonishing pace in the past few years. That first RS 2 was a strictly limited-edition model: just 2908 examples were built. In the 18 years since, more than 23,000 RS 2/4 models have been sold.