I purchased bilstien HD shocks from mercedesshop. I ordered them monday afternoon and they were at my office on tuesday morning. Saved about $170 over the local dealer's price. The frame of my car has an upside down U shaped bracket welded to the frame which limited the travel of the upper control arm when the top of the shock was unfastened. Therefore, I did not compress the spring and everything went smoothly, however, not having a manual or responce to my post I was very nervous about it. When I did them on my 190 the shock was the only thing which limited the travel of the lower control arm and I had to compress the springs.
There is a nut on the top which has to be removed and one on the bottom. I removed the top bolt using an allen wrench to keep the shock threads from turning. Then jacked up the car until the tire was off the ground. Removed the wheel. Used a 19mm box wrench and socket wrench to remove the bottom nut and bolt. Remove the old shock and inserted the new one. Use the new nut, bolt and washers (provided) to fasten the bottom of the new shock. Reattach the wheel and slowly lower the car, at the same time have one hand on the shock and guide the top threaded part through the hole in the frame. Once the tire was on the ground, I had to push down on the fender slightly to get enough of the threads up to get the nut to start, then tighten using the allen wrench to keep the threads from turning.
Whole process took about 1.5 hours. I used the spare tire jack and a jack stand to raise and hold the car and did it one side at a time. The ride is like new again.