As 'mod' is a short term for modification, it is a mod. Any change made to the original software or content must be considered a modification, whether it is 1 bit or 100 MB. Because it has been changed beyond the original design and construction of the game. USing a Game Shark or Action Replay is actually modifying code to make this available, thus the game you are then playing is _not_ the original game no matter how you look at it.