In order to achieve mass customization, companies focus on the effective usage of the Modules-of-the-shelf (MOTS) as opposed to purely relying on developing Product Specific Modules (PSM). Hence, there is a need to develop a proper methodology to evaluate the "develop PSM vs. use MOTS" decisions. This decision holds greater significance for the modular architecture, as increase in the PSM leads to decrease in the degree of the modularization of the product architecture. The compatibility issue of the MOTS and PSM has been explicitly defined in the present paper. While making the abovementioned decision, information pertaining to suppliers providing the components/modules is critical. In this study, in addition to the common criteria like cost and performance, we have also included risk assessment of the suppliers while selecting them for providing the modules. This leads to the development of a multi-objective design optimization formulation to determine the amount of MOTS and PSM in the product. To cope with the vagueness inherent in the various decision parameters, a fuzzy goal programming based approach has been applied. The design problem of a TV receiver circuit has been taken from the literature to show the efficacy of the proposed methodology.