Current design methods have focused on the integration of diverse engineering and management functions to assist in the management of the product development process. At present, existing product development tools do not allow engineering and management to quantitatively assess the cost-performance trade-offs that exist in product designs. The lack of quantitative measures of product cost-performance relationships prevents engineers from determining the cost of product features and performance, and effectively bars non-technical management from product configuration decisions. An integrated design method would combine engineering and cost relationships within a single analytical framework through the extension of probabilistic performance assessment techniques. The method will demonstrate how both engineering and cost information can be integrated into a single analytical framework, and how this information can be used to determine an optimal product configuration with respect to performance or cost. The model will demonstrate the format and nature of the engineering and cost random variables that are used. The application of the method on a combustion engine cooling pump will be demonstrated.