Meet Andy Guo, an 18-year-old Chinese immigrant, who loves driving his red Lamborghini Huracán. He does not love having to share the car with his twin brother, Anky. "There’s a lot of conflict," Mr. Guo said, as a crowd of admirers gazed at the vehicle and its vanity license plate, “CTGRY 5,” short for the most catastrophic type of hurricane. Or Diana Wang, 23, who thinks a supercar is a poor investment, because its value decreases over time. "Better to spend half a million dollars on two expensive watches or some diamonds."