Depending on the equipment installed, the new SL is between 125 and 140 kilograms lighter than its predecessor. The body is made almost entirely from aluminium while systematic lightweight design and intelligent details make for further weight savings. The lighter rear axle is complemented by the use of tube-in-tube structural elements as well as light-gauge hollow sections.

Hollow-cast longitudinal members are also employed. Despite their light weight, these elements actually enhance the strength of the body. Working as an integrated system, these measures result in a light vehicle body which is torsionally rigid and resistant to bending and which offers an ideal weight to rigidity ratio. The new model has a level of torsional strength some 20 percent greater than that of the outgoing model which already had a high degree of torsional rigidity. The extensive use of aluminium makes the new SL not only lighter but sportier, more economical and safer, too.