Incase you have not done it yet , you have to remove the bumper skin, quite simple where grill is there are plastic knock out rivets on slam panel, pop them out , on inner wings remove the torx screws then there are 2 bolts underneath , remove them, make sure you take out the computer temp sensor located on passengwer side of bumper lip, you will see it as elec connection on it, then its a case of gently pulling away sideways from wing both sides and pull bumper skin forward to remove.
The bottom valance is clipped in pos and couple screws if i rem correctly when i did mine,
It is a straight forward job dont worry , here is a link to see pics of mine fitted.
Not this site , as i got to update my gallery
http://www.audi-sport.net/vb/vbpicgallery.php?do=view&g=39