Voice Recognition (VR) and Hands Free Calling (HFC) capabilities have become prominent in the automotive industry, with over 50% of new vehicles sales equipped with some level of Voice Recognition system. With the common use of mobile personal assistants and smartphones with Bluetooth capability, customer expectations for built-in Voice Recognition and Hands Free Calling systems have increased significantly. The main systems that impact a customer's satisfaction with their system can be broken into two halves, the "usability & functionality" portion of the system, and the "core automatic speech recognition (ASR) performance". The success of the latter can be quantified by the Word Error Rate (WER) and Sentence Error Rate (SER) performance. Several parts of the voice recognition hardware/software and vehicle design need to be engineered in concert to ensure satisfactory performance of the core ASR system to meet the customer's expectations. It's not enough to design these disparate factors in a vacuum, independent of their influence on one another. In this paper, we review the relationships developed between all aspects of the vehicle system that contribute to the success of the core ASR performance in a vehicle, including the ASR engine, the body interior cabin acoustics, the levels of background masking noise, the seat position, the microphone strategy and cabin geometry. Interactions are explored between these factors and dominant influencers identified. Relationships are also established between the ASR engine performance and fundamental NVH metrics that quantify the link between the attributes, helping aid proper target setting and hardware selection to meet the customer satisfaction goals for both teams.