That is what I just said above many parts need to be changed if you want a T2x second stage (SS). However, the point is that none of the changes NEED to be done for compatibly for switching between air and EAN. There is no difference between a TX2 and B2 second stage except for cosmetics. One can use a B2 second stage out of the box for both air and EAN without issues (i.e. it does not need to be dedicated to air or EAN).
I should add, the only things I would do on a second stage is two things. Replace the old flat diaphragm retainer with the castle version and put a new exhaust on it so that bubbles are deflected a bit more.