Well, Machinery-Frank, I have access to a gamestudio pro edition (legit, not warez) from a friend, so I could mess with the source that's included with it if I wished....
There is not "source" for the engine itself. 3D GameStudio is not like Ogre or these other engines that give you the source code so that you can modify or extend the engine. You can, on the other hand, program DLLs to add some functionality or you can even replace the engine (but why buy it if you are going to replace it?).
