Originally Posted by More_Torque_More_HP

If you are boosting above the numbers produced by the Stage 1 kit you are overspeeding the turbo. We have taken the turbo to the maximum allowable turbine speed for turbo life. Anything over that does and will reduce the life of the turbo.

and to answer the question how do we know the turbo speed?: We instrument several turbos to actually measure turbine speed. We then develop an program that predicts turbine speed based on engine speed, boost pressure, boost temperatures, barometer...This program is verified against the actual readings and is very accurate.

Originally Posted by Terminator2

The max airload torque table that helps determine desired boost level is set too drop the desired boost to 234 kPa up top to help keep the turbo in its efficiency range. That is why the pressure falls off up top. The turbo can hold over 22.5 psi until 6K with a MBC on the car.

Originally Posted by Iam Broke

You forgot to subtract 14.7 psi for atmospheric pressure. It's closer to ~19.3 psig, 34 psia