Well damn....
Here's my final solution.
With 4 people in the car, its gonna be slow, thats an extra 400-600lbs it has to push.
You're beating your car up without having enough mods to use the 3.4"
I say, stick a 3.6, or 3.8 back on there, and play it safe, quit demanding more boost than it can handle.
You're gauge might be messed up, check your electrical connections, my oil pressure gauge did that, it had a bad connection, and would say i was at 45psi one day, and 12 the next, scared the **** outta me.
If all else fails, disconnect the gauge and forget about it, either the motor can somehow handle the 3.4", or it will blow.
Im out of ideas really.