Hey Eric, are you sure that your datalog display is actually in PSI and not inHg? The reason I ask is the screen shots you posted back in post# 145 show values of -22.7 and -22.9 for your boost when you let off the throttle (at the very end of the logs). I checked logs I have when running at the track, and I see around -11.4 PSI (which is around -22.8 inHg) when I let off.

Also, looking at the pics of your intake setup, it looks like you aren't shutting off the air intake on the passengers side. With the T-fitting you have, wouldn't some of the compressed air from the turbo get pushed into the passenger side air intake pipe?