lol, I knew one of use would get confused... sorry about that. I was trying to say if you just changed the opening theme and left TEC 3 alone you shouldnt have to worry about the song with words playing during the acutal gameplay.
If you change the opening theme and it still plays TEC 3, you can try and taking the Entrechment Soundmusic.sounddata file and copying over the new Diplomacy. Then replace the opening theme. And it should work. At least its how its working for the mod im using.