All good points.
One question, how do you break in the pads and rotors?
I`ve always braked carefully , no hard stops, gentle on the peddle for at least 200 miles. never had a problem.
Recently I replaced the pads and rotors on my 560 SEC, with ATE power discs and Oem pads. After 2000 miles everything is great.
If your doing this yourself how do you set the bearing preload? I don`t have a dial indicator so I thighten the nut until the rotors will just about turn, then back it off about a third of a turn. check for excsessive play and put it back together. Take it for a ride and check that the hubs are not overly hot. Always repack the wheel bearings,and change the grease in the hub.Use Mercedes Green grease.
Your hubs could be getting to hot and warping the rotors

John