I agree with nelbur - cupping is not generally an alignment problem, and a bad camber setting would show up as excessive wear evenly spread around the inside (or outside) edge of the tread. Since the car hasn't always been this way, I suggest you look for worn or broken suspension or steering parts, although one would expect the dealer's alignment tech to do this as a matter of course.

It's my understanding that there is no adjustment for camber in the stock suspension on these more modern cars. When I fitted 40mm lowering springs (Vogtland Sport kit) on my '06 E320CDI (W211), the wheels were visibly tilted in at the top and quickly wore the inner edges of the tread down to the cords on all four corners, but it was an even wear across the face of the tread with no cupping and no excessive noise.

I solved my problem by fitting a trick set of lower control arm bushings from K-MAC in Australia that allowed for plenty of camber adjustment; with the improved stance, lower center of gravity and stiffer shocks (Bilstein B8), she corners like she's on rails and the tires have worn evenly across the tread with amazing tire longevity.

Good luck and let us know how you make out.

Best Regards,
Rob

__________________
Robert Fini

'12 ML350 BlueTec, 111k
'06 E320CDI (x2)
'05 T1N Sprinter 2500/Pleasure-Way Plateau TS, 72k
'97 C36AMG, 325k (son's)
'94 E320T, 249k
'93 190E Sportline LE, 168k (daughter's)
'84 190E-2.3/5spd (Stage Rally Racer)
'66 230 W110 Sedan (Barn Find, Vintage Racer build in progress)