Courtney,
Having the Dealership do this work will not avoid the possbility of a broken GP. You have to assess MB dealer service vs indie. A wealth of info on this subject here. My dealer told me not to attempt removal until car will not start (200K @ that time). I rejected that and followed posts and sucessfully removed/replaced myself.
Do them HOT, Alot juice, Alot of tapping with a small hammer on socket handle, Alot of patience, (3X the above @ 10min intervals, then I removed) Maybe I got lucky.
MB mech's are good, but no guarantee on this work preformed.

Before you get jack up, how many are dead, what are the resistance values ??

Good Luck,

__________________
Gary
Experience is something you get, Just after you needed it....
'99 E300 295K, '83 300D 220K, '75 240D 185K sold
'80 MCI Bus Conv DD 6V92TA, w/4 cyl. Kubota diesel GenSet 12.5KW