Porsche are intent on building a production version of the 918 Spyder, and offering it for sale to anyone with deep enough pockets. It stuffed the sexy all-wheel-drive roadster with a 500-horsepower V8 and two electric motors putting down a combined 281 horsepower. Insiders say the production 918 is likely to go on sale within five years. However, like all Porsches, it will need to make money, despite its ‘halo’ status within the firm’s range.