something is definitely wrong to do such low #s on 15psi on a gt2540r. unless people are getting sold the wrong turboes and dont know it. esp with an enthalpy tune, even a basemap, it should do much better. maybe boost leaks or something.

gt2540r on 15psi with a decent tune should be no less than 350. people running 18-21 psi are easily hovering around 400.