Vehicles sold outside of the North American Region (NAR) are equipped with very different outside rear view mirrors than NAR products. The Rest of World (ROW) mirrors have an aspherical section on the driver side mirror. This provides the driver with a much wider view of what is behind the vehicle. The transition from planar glass to the convex (aspherical) section is marked with a dotted line. The outer 35% of the mirror area is aspherical.
The ROW passenger side mirror has a slightly smaller radius of curvature than US legislation specifies for the NAR mirror, thus providing a greater field of view. It also does not have a 'Objects in the mirror are closer than they appear' message stenciled on it, because no government in the ROW marketing region has thought it necessary to legislate that this warning appear on the rear view mirror.
I had ROW spec mirrors installed on my Golf, and missed the aspherical section when I traded in the Golf for the Phaeton. So, I picked up a pair of ROW spec mirrors, and retrofitted them. The process is quite easy, and you don't need tools to do it. If you do change the mirrors, keep the old ones, because the car will not pass a North American safety check with the aspherical mirror on the driver side, and with the warning message missing from the passenger side.
Adjust the mirror so it is pointing fully inward
Put your fingers behind the mirror, and gently pry it out
Make sure everything is warm (room temperature) before you do this.
Be aware there is limited room for movement with all the wires connected
One set of wires is for the heater, the other is for the anti-dazzle dimming.
Take careful note of how the connector is attached to the mirror, and how the wires are routed on the back face of the mirror
Vertical differences between mirrors
Horizontal differences between mirrors
This is where the real benefit of the ROW design is.