by Mike Krumboltz The Toyota Prius is making some noise, literally. The hybrid car that's eerily silent at slow speeds is adding a bizarre option: A noise-making gadget that will sound like a motor. A reasonable person might ask why would anyone want to pay $149 for something that just makes noise. According to a buzzy article from CNN Money , the main point is to alert pedestrians when the car is nearby. Oh, and also, it's the law in Japan,