I got the same problem. Got a new engine. A new CT9 turbo ( not rebuilt but really new ). A new HKS actuator. Got full boost about 3500 - 4000RPM. i wanted to be stock so i made a T piece betweeen the hose between the turbo and actuator to make the hi/lo button work. Now i dont want it anymore so i did the bypass as we all know. Still i got the boost problem. Dont have a boostgauge , only the three lights on the dash. Can upload a little clip tomorrow