Plastic Omnium (PO) provides plastic fuel and emission reduction fluid systems for car manufacturers. These products, must be customizable to respond to different manufacturers needs while being compliant to ISO26262 and A-SPICE standards. To satisfy these needs, PO employed a development approach where system functional specifications are document-based, and software architecture design conforms to AUTOSAR. However, this approach requires to manually translate between textual specifications and software models, usually rising inconsistency and maintainability issues. This paper reports on the lessons learned with the introduction of a full model-based approach to solve the issues identified in its former approach. The proposed approach is evaluated on a real case study using the open-source Papyrus tool.