The introduction of carbon fibre composites into the high volume automotive sector challenges the design process, since these components not only need to be light but also producible in a cost-efficient manner. One way forward is to introduce manufacturing constraints into the design process, but such constraints affect the freedom of design and opportunities to tailor material properties. This work examines the trade-offs between cost-effective design for manufacturing and the weight optimization of composite structures. This will be achieved by introducing restrictions to the number of plies allowed in structural optimization in order to simplify pre-operations and reduce overall manufacturing investments. Both integral and differential design solutions are considered. It was observed that differential solutions were always more cost and weight efficient than the integral solution, however too severe manufacturing constraints result in an expensive final part due to the additional weight.