600whp and 10s out of my STI

23-24psi on 93
26-27psi on vp c16

We tried removing the air filter and adding 2psi boost but the car wouldn’t make any more HP, just more TQ. 26psi = 611whp, 28psi = 613whp. We thought the turbo was maxed out but now I’m wondering if the leaking uppipe gasket had something to do with it.

Thanks guys