correct more air being forced in the engine = more power!

You are looking at it that 23psi is 23psi and the same volume of air no matter what the turbo!

compare the size of a T3 to a T4 the reason for it being bigger is so it can shift more volume of air per psi!

So take a T3 running 23psi a T4 wil only have to say run at 17psi to shift the same volume of air!