FSX Update AI

I went through all of US Airways world of AI package and updated all the textures to American Airlines to help make scenery a little more current. However I was curious, the American Airlines most updated package, world of AI, still has the MD-80. Would I somehow be able to swap the MD-80 out with one of the new A319's or 321's? If so how would I go about that? Downloading model and textures and swapping them out etc.