In the automotive industry, many car manufacturers are exploring the possibility of replacing traditional welded sheet metal body parts with a single large aluminium High Pressure Die Cast (HPDC) component. This approach offers several advantages including manufacturing cost reduction through part consolidation, improved geometric freedom, recyclability and the inherent lightweight properties of aluminium alloys compared to steel. However, HPDC often introduces material defects and a variation of material properties that needs to be considered when performing structural simulations. Typical defects are oxide films, intermetallic phases, and pores. Pores in particular acts as crack initiation sites and decrease both the ductility, as well as the tensile strength. A key challenge is therefore to model and simulate such defects and microstructural features to virtually predict the resulting material and fracture properties. This could serve as a basis for macroscopic material models used in e.g. crash analysis. In this contribution, we perform virtual testing by FE simulations of microstructure models with statistical variation of defects.