Perhaps this is obvious, but I learned today that it is possible to secure the Audi front winter mats using the same hardware used to secure the standard carpet mats.<p>The winter mats have two indents in the proper places that can be easily punched out. The round slotted plastic pins from the standard mats can be easily pried out and placed into the holes you've made in the winter mats. <p>It takes quite a lot of pressure, but you can force the pins through the thick winter mats and into the receiving holes on the floor. The teeth on the pins must be lined up properly, forced in hard, and then turned a bit to lock into place. Voila: mats that don't slide around.

If you would prefer not prying the parts out of your summer mats, Audi will sell you the 3-piece plastic "clip" that goes into the mat as a separate part. Part number is ZVW 178 001, and they cost $9.16 for four "kits" (for 2 mats) from Clair.<p>I've found that my winter mats don't move around much anyway, but this is a neat solution to ensure it. (You can also just punch a hole in the rubber and work it over the peg on the floor. A little "inelegant", but it should work).