A polycarbonate resin composition includes a polycarbonate resin, syndiotactic polystyrene, and modified polyolefin compound including a polar functional group on a polyolefin backbone. The location and size of the sole stress reducing feature, and their relationship to one another and other club head engineering variables, play a significant role in selectively increasing deflection of the face. At least one user input is received from each of the plurality of stakeholders selecting at least one test case selection criterion from the list of test case selection criteria and, for each selected test case selection criterion, assigning a criterion priority.