Question: what is the difference between an audi a4 and s4?
Answer: Pros of Owning An S4 Over An A4 The Full Package – while the S-line appearance package on many A4s may cause those cars to look like an S4 – it's not the full package. The S4 has upgraded brakes (larger rotors in front and vented in the back), sway bars, differential, suspension, wheels, etc.