I'm just reporting the facts
. It would seem to me that a restrictive exhaust would lower flow, turbine spin and boost? and a high intake pressure would be a result of having lack of flow there letting the pressure build up.
The car when I purchased it, didn't have a boost gauge. When I put one on it would go to 9 with a normal range of 10-12. It would boost to 1 at 60 and 5 at 62. I tracked it down to the ARV.
It had an intake turbine bypass so that it would not run boost even with the turbo spinning good. It was called an ARV. It had a fairly complex system that would bipass the intake air until the car got to 65 and had a fairly high load, then the ARV would close, allowing the air to flow into the intake.
I figured that if the turbo is spinning, it should be boosting so I disconnected it and immediately got boost at any speed above 35-40 cruise.
You can never hear the turbine whine you can not hear the exhaust much. Still 30 mpg isn't that bad for winter driving with snow tires on all wheels.