This compact executive car began production in 1999 and is still going strong today. The Audi S4 Quattro is the top-performing version of some of the A4 generations. The vehicle is a sport compact and ranks as the fastest, most sport-focused model of the A4s “B” automobile platform. The Audi RS4 has been through four distinct generations of the model, including the B5, B7, B8, and most recently, the B9. Today the RS 4 sports an 8-speed transmission with a 2.9 L twin-turbocharged V6.