Okay I found this out when Draginol was posting about Map Size Changes - for your information - Crusade abandons all of the standard GC3 files and only utilizes new versions of the XML code under .../Galactic Civilizations III/DLC/EXP2_Crusade/ where modified copies of the ship designs game data XML files are located.  Also mods are accessed under a new ../Users/ xxx /Documents/My Games/GC3Crusade/ folder - everything under the old mod folder .../Documents/My Games/GC3Civ/  is ignored as long as the Crusade Expansion is enabled in Steam (if you unclick the Crusade Expansion in the DLC list then it revert back to looking at the old data and runs the old GalCiv3.exe executable (ie there is a number executable also for Crusade - GC3Crusade.exe) ).

all of the techs are now defined in MasterTechDefs.XML under the new DLC/EXP2_Crusade/ folder.  There is only one tech tree file as far as I know and parts of it are enabled or disabled by Racial Abilities.

Of course be aware that any and all typos or mistakes in editing these files might prevent you from running the Game (I have donet it many times already forgetting comments or making typos).