Re: what needs to be changed? LCD vs digitizer or both?
The glass and the LED panel, at least, and possibly the LCD panel. It's a lot less work (read: cheaper for you) to just have the whole screen replaced in one piece. (If you're going to try it yourself, you might be successful, but be prepared to pay a LOT to have the entire phone checked when you have to bring it in for repair (read: very expensive) because you did something wrong in replacing the screen.)