In my experience, I would advise to ALWAYS use a spring compressor when changing struts. It is extremely dangerous not to, not for the car but for YOU. You could be killed if done incorrectly.

If the car has MacPherson Struts, then there is a compressor designed specifically to decompress. This tool can be rented pretty much anywhere for like $10/day. It is pretty self explanatory too.

I have never changed the struts on a benz, but I have on all my VWs. I hope I provided some insight.