I too was going to suggest checking the flex disc. If it gives way at highway speed, your airbag may deploy suddenly, which would be a BAD thing.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280