This paper presents applications for an integrated shape- and topology (IST) optimization approach of structural systems. IST introduces additional geometric and loading conditions to the design space of topology optimization. That is, the design space for a Solid Isotropic Material topology optimization algorithm as well as the complex surrounding structure can be varied. Importantly, large scale shape variation is performed in conjunction with topology optimization, rather than post the topology optimization step. This paper discusses the relevant optimization and parameter studies for automotive design. The case studies presented range from single parts to highly complex assemblies. Automobile body structures that combine extruded beams with cast joints are an important application of IST.