I recently did this job 2 years ago. You should remove the rear
differential, by disconnecting the half-shafts and the drive shaft.
Depending on the bolts used to fix the half shafts to the differential,
you could have a good time or a bad time. My shafts where connect by
tri-square bolts( 12 point hex allen type) I had to purchase a special
male drive ( M10  from Stahlwille ) 1/2 in. drive. The new bolts from
Mercedes where reverse torx cap screws. So the drive I purchased was
used once to remove the bolts and not to replace the bolts. I was pissed
about that.
Anyway, the shafts disconnected, the two rear bushing bolts and the
front support bolt out, the differential drops out. ABS cable is
connected to the differential, remove it.
The bushings require a pressing tool to get out and the new back in. You
can rent it from Performance Products. But I created my own tool with
fine thread 1/2 bolt and various pipe cap and flat steel scraps. The key
is to get the press depth to match the depth of the original bushing. So
before you remove the old busings feel/note the reveal of the bushing in
relation to the subframe. Pressing the bushing out with the factory tool
will be easy. Without the tool, I decided to disassemble my hacksaw and
thread the blade through the bushing hole and proceeded to saw the
outside bushing sleeve from the inside. Once I weakened the wall of the
bushing in 2 spots, it was easy to punch them out of the subframe with a
chisel.
Clean up the holes with sandpaper and put vasoline on the sleeve and the
new bushing. Press them in. Be careful to press only on the outer edge
of the bushing and don't press them in any further than your original
depth. then raise you differential and attach everything. Your done and
you save a small fortune over the dealer cost. Oh make sure you get the
a.s end of the car up as high as you can. You will appreciate the
shoulder room. Let me know if you have any questions. I may have missed
a key activity. The guys in this forum are experts and will have other
suggestions , good luck

JB
99 E55
88 300E