I replaced both rear hubs with the bearing. On my car, some of the lug threads were stripped when I bought it, and I tried the "helicoil" insert (search on "rear hub") which worked OK. However, I autocross almost every weekend and wanted a more reliable solution. So I got 1 hub from LKQ and 1 from MrMoPar. Both were under $75 + shipping. You will need to get a new locking nut from Mercedes, a Metric size 30 12-point socket, and all the torque you can muster (while the wheel is on the car) to loosen the nut. Overall not a bad job, but you will have to check the toe alignment strut and adjust the cam as necessary (measure toe before you tear it apart). Good luck.
Mike