Even after mods we wouldnt have much of a chance. This dude a cople towns over was selling a slightly modded S4 (intake, exhaust, Piggy back, drop) and was @ 398WHP. 10 second car every time. Those rides are quick
The S4s are pretty nice cars. I haven't raced any yet though, so I don't know how they would compare. It's kinda sad when people buy those cars and get autos... I just saw the RS6 (twin turbo V8) in the parking lot of Enterprise where I got my rental while I had my RL fixed, but it was a friggin auto. I'm pretty sure they come in manuals, but this one was sadly an auto. But the S4s in the late 90s, maybe the 2000 and 2001 model year too, had twin turbo v6s with those numbers that you posted. The new ones you see now have the big 4.2L V8s (naturally aspirated). I'd have to look into the numbers on both for power and 0-60 times, so I can't give an estimate of who would win, us or them. My guess is that they will probably beat us. I just wanted to clear up the two different type of engines in both of them.
A friend of my wifes has one. She (yes she ) let me take it for a drive when she as over one day and it was a very impressive car. Being a stick it was fun to drive but I think an auto would give one hell of a whole shot off of the line.