I've raced an S4 on the freeway. 2 times as soon as i "broke in" the car. I had about 1200 miles with no mods except the Volk TE-37s. I kept up with one til near the end of fourth gear and from then on it just passed me like nothing. Did the same thing another day on the freeway. Now that I got my boost controller, uppipe, shortshifter, and exhaust, I am really anticipating another run with one of those. I know that the S4 is quite fast but am Extremely confident about taking one out.