i like the old A4 really alot. 
 
i suggest you get red/white lights for front and rear to get an even sportier look. other than that it is already looking good. 
![Clap    [clap] [clap]](/images/smilies/icon_smile_clap.gif) 
 
if the money is there, get some bigger rims. I love the S4 wheels, maybe that would be an option?
all in all it could look like this one here...