Smart move to adjust the 'nut' first!!
I have a02Infiniti Q45 and have been improving my driving over the last several yrs. the Q has an onboard mpg screen that has been a great help.
My daughters boyfriend just got a 99 A4 1.8 4 door.....don't think it has onboard mpg...does the Avant?
I also hear what you are sayinh about the stealth look. Look at the temp grille block I did w/ clear plastic. It made me a believer!
Also, I think your A4 has abs under pans. I 'tested' smothing uot the ones on the Q and got good results so far. My goal is to hit 31-34 mpg on my next cross country trip in feb 2010. I have gotten 26mpg avg 69mph oover 1700 mile last yr. that was just by driving better.
You have to realize that some mods, like removing the roof rack can be done cleanly.......we're not going to make you run a boattail tomorrow......