Driven by electrification and increasing demand for in-cabin comfort, the automotive industry faces a paradigm shift where the absence of engine masking noise makes the vibro-acoustic performance of auxiliary components, such as Heating, Ventilation and Air Conditioning (HVAC) systems, a critical design factor. This Master’s Thesis, developed with O.R.S.A. (Off-Road & Special Applications) Department of DENSO Thermal Systems and technical support of HEAD Acoustics, focuses on the structural validation of an HVAC mock-up manufactured via Stereolithography (SLA) for heavy-duty applications. Building upon a critical analysis of a preliminary study exhibiting limitations, specifically a baseline Finite Element (FE) model lacking accuracy at medium-high frequencies and an experimental dataset compromised by low coherence above 100 Hz, the objective is to develop a high-fidelity structural "Digital Twin" validated through robust experimental correlation up to 500 Hz.