Some concepts become production cars. Some become nothing. But the Maserati Boomerang ended up influencing everything from high-end sports cars to the Volkswagen Golf. Debuted at the 1971 Turin Motor Show, this one-off was updated the next year to become fully-functional, with a 300+ hp V8 engine, a top speed of 186 mph, and gauges mounted inside the steering wheel. It was penned by Giorgetto Giugiaro, who designed the original Lotus Esprit and the Nikon D4, among many other notable items.