Question about CLS and CL
The suspension on the CL appears to be the big difference. It has Active Body Control which is an active suspension system, using coil springs. It continually adjusts each wheel's suspension to compensate for road differences. There appear to be a few more "goodies" on the CL as well, such as the Navigation system standard and 14-way adjustable seats, standard heated seats, power rear sunshade, etc.
CLS is built on W211 E-class chassis.
CL is built on W221 S-class chassis. It is far more advanced in every area.



