2013 Audi S4 steering problems

My 2013 audi s4 exhibits an alarming tendency to weave from side to side without a steering input. This occurs without a change in steering wheel position, vehicle speed, or change in road surface or prevailing wind direction. It is more pronounced at highway speeds and when wheel is centered at 12 o'clock but does occur at all speeds and steering vectors. Audi dealership notes the problem and blames the new electric steering system but states it is a "characteristic" of the system and is not a defect.

Audi's electronic assisted steering on my s4 exhibits unpredictable behavior which could result in an accident. It has a "notch" at 12 o'clock where the car usually does not respond to wheel inputs until you turn it more than an inch in either direction. When it does finally react, it often overcompensates. It does not always happen however. Sometimes the notchiness is present, sometimes it's not even on the same steering settings/same speed. I can not keep the car going straight at times.