A lot of people have a side hustle. Some people buy things on the cheap and resell them online. Others buy broken down used cars, repair them, and sell them for a profit. The latter is a form of car flipping, and it’s a relatively cheap way to make a little extra cash if you know what you’re doing. When you have deeper pockets, however, flipping cars is about buying limited-production models like the Porsche 911 GT3 or the Ford GT, letting them sit until demand and value go up, then selling them for huge profits. Well, Porsche has had enough of the practice and will begin vetting buyers of its limited-production GT models.