I don't remember where but before I bought my M3 I was thinking of maybe buying a B8 S4 and I saw a review where they said that they did the 1/4 mile in 12.5 at 108mph and for me that made a lot of sence since I raced one with my 12.5 109mph STI and we were exactly equal , exept for the nose he took when we WOT because of the my turbo lag ! And also there is this guy that pretty much confirm the thing :
http://www.dragtimes.com/Audi-S4-Timeslip-22323.html