After showing off the amazing 918 Spyder hybrid supercar at Geneva earlier this year, Porsche said that if 1,000 orders were placed, it would turn this concept into reality. It looks like enough buyers have stepped up, because the project now has a green light. In the package is a 500-hp V8, a couple of 109-hp electric motors, and a lithium-ion plug-in battery pack. When the 918 does roll out of the factory, it will be the most expensive production Porsche ever, since the company is charging 500,000 euros a pop, around $630,000. Still, being able to do 78 mpg makes it a money-saver in one respect.