A popular strategy in structural dynamic modelling is breaking the structure down into separable, manageable substructures. One can choose the most efficient way of modelling the substructures, before synthesizing the full system model. System Equivalent Model Mixing (SEMM) is a new method that allows mixing of frequency-based models, either of numerical or experimental nature, to form a hybrid structural dynamic model. The method expands measured data onto a numerical mode manifold using Lagrange-Multiplier Frequency Based Substructuring (LM-FBS). Hence, SEMM combines the DoF-space of the numerical model with the dynamic properties of the measured substructure. In this paper, SEMM is applied to a complex vehicle component. Frequency Response Function (FRF) measurements on the component are used to enrich the uncalibrated Finite Element Model of the component. The resulting hybrid model comprises interfaces in six degrees of freedom, which is required for the connectivity to neighboring structures in the FBS framework.@en