With a 542-horsepower engine, the XJ220 was, for a short time, the fastest production car in the world. When plans for this car were first announced, it was supposed to have a V12 engine, but that was later changed to a turbocharged V6. Still, that was enough to get it from the zero to 60 in about 3.5 seconds and to take it to a top speed of 217 miles per hour. Despite that amazing performance, it's a relative bargain today. This car's estimated value is roughly half its original sticker price of $625,000.