The front end parts... and why.
My D4 had a minor vibration in the steering wheel under braking... I can see you all thinking warped rotors. Except the vibration didn't happen all the time. There is a certain VIN range that are know to have this issue.
The fix starts with a new steering wheel and goes on from there.
So if you have a minor vibration in your steering under brakes get it checked out.

