LuvnhatemyA6

i've always had some wind noise from the drivers outside mirror, tonight I noticed that ouside air is coming around the mirror in when the sunroof is open. There must be a bad seal.

Now the question is : can you take off the little piece of trim and then the mirror, without taking the whole interior door trim off?

A6vanilla

No..unless you break the triangular piece of plastic trim and then replace it. The door trim removes with two screws..one fore and aft at the upper bulge at each end.
Pop the window switch (rubbery with switches) by putting a thin phillips head screwdriver in the hole on the underside of the armhold it's mounted in and pressing upward until the mount comes out.
Disconnect the switch and pull the whole panel upward.
THen the triangular cover can be removed. The seal is best put back into shape with a hairdryer and a couple of clamps to restretch it into shape. Reapply and reassemble the door trim. voila.