Does this help?
For Model Year 2016 Mercedes-Benz is renaming/reorganizing some of our models. If you think of the C/E/S as the building blocks and then the GL as a prefix for SUVs, SL as a prefix for roadsters and CL as a prefix for coupes, I think it makes sense!
My chart isn’t perfect. I left out the S-Coupe and E-Coupe that are staying the same. Also, the B-Class is a strange case and doesn’t fit here. It is a work in progress! We’ll get it eventually.