GT/GTS Conversion

So I know this may be an extremly dumb question but I couldn't help ask. I have a 2000 GT Toyota Celica, it's an automatic, now my question is if I wanted to swap my engine to a GTS motor, is there such thing as a GTS Automatic engine that I would have to purchase or does it matter, I guess I dont get how the swap would work. I truly have now motor/engine knowledge and dont want to buy something that isnt going to work. Could anyone please help...