Anything over 16 psi on a T25 (pump gas) gets slower typcally. Stock boost is over 14.
14b is a great turbo. I ran mine at 18 psi (be sure to get the necessary mods to do that) and 24 psi on race gas. I did mid 12s on mine, others have done better. Unless you want to go bigger right out of the gate, but make sure the car is properly setup. 14b is a great turbo to learn how to tune on.