No power at top end with SR?

[Silverbullet]

hey i have a problem with my SR. Im just not feelin it at the top end near red line. It will boost up fine in mid range because i can feel it pull hard but once its at full boost past 4-5k RPM, i just dont feel it pull anymore. The first thing that comes to mind is boost leak correct? Well, it just dosnt feel like a boost leak. If there was a boost leak, u'd feel it just suddenly cut off. With mine the power just goes away. I've also observed my boost guage carfully as well, it dosnt fall bakc down after hitting full boost like if it would with a boost leak. I've done compression test numerous times as well. 160psi for all 4 clyinders. Problem with the turbo maybe? Im stumped.