This paper reflects an efficient and comprehensive approach for vehicle sound optimization integrated into the entire development process. It shows the benefits of early consideration of typical vehicle NVH features and of intensive interaction of P/T and vehicle responsibilities.The process presented here considers the typical restriction that acoustically representative prototypes of engines and vehicles are not available simultaneously at the early development phase. For process optimization at this stage, a method for vehicle interior noise estimation is developed, which bases on measurements from the P/T test bench only, while the vehicle transfer behavior for airborne and structure-borne noise is assumed to be similar to a favorable existing vehicle. This method enables to start with the pre- optimization of the pure P/T and its components by focusing on such approaches which are mainly relevant for the vehicle interior noise.After installation of the pre-optimized P/T into the vehicle prototype, the actual interior sound is benchmarked followed by a sound cleaning process to start with the elimination of obviously disturbing sound shares. The sound improvement is then performed on this pre-optimized vehicle concentrating on realistic hardware potential elaborated. Improvement measures are realized in hardware and finally verified with respect to their impact on the interior sound quality.