I have a 1992 300e and am in the middle of doing the same thing. I removed the lower a-arm without a spring compresor and almost killed myself. The spring, even with the suspesion fully unloaded was under a lot of tension with the strut still attached. I would consider using a spring compresor, I would be concerned that as you unbolt the strut the spindle assembly (steering knuckle) is gonna come down fast as the spring decompresses.
I hope this helps and I am accurate, all I know is when I pulled out those a-arm bolts that spring really let go, honestly lucky I did not get hurt.