Heres a guide i found off
www.a4mods.com
Before AfterI picked up a set of Matte finish In.Pro mirrors from a group buy on AZ a while ago. I just got around to doing the writeup on the install. The process is very easy and should only take 20 minutes. You have to be careful tough, because you coudl break some of the platic tabs during the process.
SUPPLIES -The supplies are easy: The mirrors, and some basic tools (screwdrivers)
First thing you need to do is remove the mirror itself. To do this just point the mirror to the floor using the interior controls. When you get enough room to fit your finger behind it, place your finger there and pull it towards you.
There are about 3 clips which hold it in place. Do this carefully as to not break the clips.
The mirror will pop out as pictured to the right. You will then have to disconnect the two electrical connections on the rear of the glass.
The next thing you want to do is take your screwdriver (I believe it was a phillips head) and unscrew the two screws located at the bottom of the mirror housing
With the above two screws removed, position your hand like pictured to the left, and press down with your thumb where the arrow points.
You will feel the bottom of the housing pop out in the middle
Work your way around the bottom edge of the housing until the bottom piece disengages.
With the bottom portion removed, you have to lift the housing upwards to disengage it. It was easiest for me to start at the section closest to the car.
This part WILL require PATIENCE...you will probaby feel like it wont come off, but be CAREFUL and keep working with it....it will come off.
The installation of the new mirrors is just the same in reverse.
Final pics: