Geez Guido, now I'm scared for you! Shaving 10mm of meat off of any rim is going to compromise their integrity. I did that once to a set of wheels and took off only 3mm after consulting with the manufacturer. They said anything more was unsafe. Don't do it!
During my research before buying new wheels this spring, I found that the SL can carry wider rear rims with greater offset than the 500E can handle without interference. The SL will mount 10" wide AMG monoblocks up to ET 17, while the max for the 500E is 10" wide at ET 19. Small difference but those are the maximum limits. Other variables are the actual shape/profile of the inner rim face, which needs to clear the brake and strut components, which is why various styles in the same sizes may require different offsets.
Guido, didn't you also mention in an earlier e-mail that your rear suspension compresses quite easily and bounces for several cycles after you push down on the trunk? That seems unusual and does not compare with my car. What have you traced this to?
Good luck, but please DO NOT risk your life for a set of wheels!