What kind of HP does the stock have, am I thinking of the wrong car?
http://rs4.prt.org/movies/ursport/ursport-evo6-race-half.mpg<ul><li><a href="http://rs4.prt.org/movies/ursport/ursport-evo6-race-half.mpg">http://rs4.prt.org/movies/ursport/ursport-evo6-race-half.mpg</a></li></ul>

...I don't know the exact specs, everybody get different results, but 4.5 seconds seems reasonable for that car.