Building to customer order enables manufacturing to better respond to market conditions. The time lost between changes in customer preferences and product mix disappears and customer demand can drive production. A build to order system has IT system requirements that go well beyond current automotive IT systems and structures. The investment required may be significant, but not much beyond current investment levels. Indeed, simplifying the system should bring down the long-term costs of systems maintenance. Build to order releases the flexibility hidden within the entire supply chain, allowing it to act at the speed of market change. Optimization applications directed at improving the operational cost effectiveness of business critical operations in principle should be linked; build to order allows optimization of the whole of the supply chain.