The S4 is Audi’s high-performance version of the A4 near-luxury sedan that was added to the lineup in the 2000 model year. The S4 was not available for the 2003 model year and returned for 2004 with a 340-horsepower V8 engine, available as a sedan, cabriolet or Avant. In the middle of the 2005 model year, the S4 was restyled with a number of exterior updates and a 340-horsepower 4.2-liter V8 engine. The lineage of the S4 can be traced back to the original Audi Sport quattro and the quattro permanent all-wheel-drive technology that has been proven on racetracks throughout the world. Audi used the Sport quattro to win the World Rally Driver's Championship in 1983 and the Driver's and Manufacturer's Championships in 1984.