How hard is it to switch the entire display unit on the MacBook Pro 15" Retina? I am referring to the entire top half of the laptop with the display with another like unit? Can it removed as one entire unit or is it more complex than that? I know with Dell or HP systems you can remove the entire top half and replace it with another like replacement. ---------- For example. Let's say I have an LG screen and wanted to replace it with a Samsung screen. I have two identical MacBook Pro's. One has an LG screen and the other has a Samsung screen. I would just want to swap one for the other.