LOL that's a crazy price.
12,000k wouldn't be brighter than 4300k. Headlight lights usually range from as low as 3000k to 12,000k. It goes from a yellow light to white to blue, violet, then ultraviolet. 4300k is the brightest temperature. Same as our Sun's colour output. 12,000k would just mean the light is more blue/purple and slightly 'less bright' than 'brightest'. Just felt like explaining.