Fit the coin holder in the front leading edge of the center armrest, it will be a tight fit, you will have to use some force to install it. Note the plans I've included. You may think you have the wrong part since the coin holder is about 5 mm too wide for the armrest, but it will fit just fine, you just have to force it. Once in the armrest, it will be held in place due to friction. Face it so that the coins side out towards the back of the car. Now it is firmly attached, but you can also remove it if you are going somewhere outside the car where you will need lots of change.

I have personally performed this modification on a 1996, 1997, 1998.5, and 99.5 A4 with no problems. Some people have reported that this modification does not work for their A4's armrest, but I think they were just not using enough force to place the coin holder in the armrest.

Audi part number: 4A1 941 577 01C