Digital Twin (DT) and IIoT (Industrial Internet of Things) are significantly changing the automotive industry landscape. This research paper discusses the use of DT and IIoT technologies in the vehicle lifecycle. DTs as a virtual replica of a vehicle allow engineers to perform digital simulations, and run virtual crash and wind tunnel testing, streamlining the production process. Additionally, IIoT enables automakers to collect and analyse data in real-time; all of which will improve quality control, including predictive maintenance, maximizing cost efficiency, training workers, and more. Combining the potential of DT and IIoT not only makes developing autonomous vehicles practical, it enhances the customer experience. This paper aims to provide a definitive account of how automakers can use DT and IIoT to boost efficiency and foster new products, services, and aftersales innovation which will transform the automotive industry in the future.