First, it might be useful to explain what building a race car means, since it may not be apparent to the vast majority of people. Some race cars, like open-wheel Formula cars, are designed and built entirely from scratch. But most sports car racing starts with a normal street car. "Building" one means taking a factory car and stripping it down to bare metal. You tear out the interior, weld in a heavy-duty roll cage for safety, and upgrade the brakes, suspension, and cooling.