The ST706 uses a 2" flapper and flush valve.
The ST743S Drake tank has a 3" flapper and flush valve.
It's not a pressure flush, it works on gravity.
The Drake uses a siphon flush
The Carousoe uses a wash down flush.
The trapway on the 706 is smaller and has tighter bends than the 744S
The seats are compatible.
You can't mix them up.
If you want something with G-Max, you need to have a tank that matches up with the bowl.