[johnno74]

The SDK for a game is the collection of tools used by the team that developed the game to edit the game data files, and the documentation for the data files. The content of a game (maps, textures, sounds, models, missions etc) is stored in the data files, and the game engine is the program that "runs" those data files. In some games a lot of parameters are hardcoded in the game engine, in other games like SH3 most of the parameters (such as the AI parameters, the sensor parameters etc) are also in data files.

Myself, I don't think there is much point in asking ubisoft for their SDK. The tools that the community have developed are pretty damn impressive, a lot of the modders here probably know the ins and outs of the game engine as well as the original developers.