Audi celebrates a landmark anniversary in style at the Goodwood Festival of Speed this weekend (24-26 June) with a fitting reunion. One of the world's greatest rally drivers, Hannu Mikkola, will be reunited at the annual speed event with a car that changed the face of the sport forever.

In October 1980, the "Flying Finn" tested an Audi quattro rally car for the very first time in public - a prelude to the remarkable 25 rally championship titles won worldwide by Audi between 1981 and '85. Mikkola will drive that very same pioneering Audi quattro, which rattled the sport to its core, at a motorsport event for the first time since the Portugal test 25 years ago.

The Audi, which has been beautifully restored by Manchester-based quattro enthusiast John Hanlon, changed the face of rallying forever. Whether on dry or wet tarmac roads, snow and ice or indeed muddy forest stages, four-wheel-drive rally cars became the norm the world over and to this day still dominate the sport.

Meanwhile former double German rally champion, Harald Demuth, drives an Audi Sport S1 quattro owned by Milton Keynes-based Audi UK. This 1985 "Group B" Audi, boasting almost 400bhp in "normal" trim but in excess of 700bhp in "Pikes Peak" guise, was the last development carried out to the "rally" quattro.

The undisputed "King" of the Pikes Peak hillclimb, Bobby Unser, who won the legendary American hill race 13 times including in 1986 with Audi, will also demonstrate a flame-belching Audi S1 quattro Pikes Peak on a rare visit to the UK. A fourth Audi quattro, a 1983 A2 machine driven by Mikkola and owner Hanlon, will contest the new 1.75-mile rally stage.

The most successful modern day sportscar in recent times, the Audi R8, will be on display throughout the three-day event. A four-time winner of the Le Mans 24 Hours, the Audi R8 has scored an incredible 54 outright race wins from 66 starts.