This is the only dyno curve with a boost curve included.
Unfortunately not a stock N52.
This car has catless headers and 3IM which both should LOWER boost as they allow more air to flow thru the engine.
So it looks like at 7000rpm it makes 5psi boost. Your results may vary due to your mods.
The nice part is that the boost curve is very linear so predicting boost with different pulleys is easier and there is some calculations/scientific involved, not just guessing.
So for this particular car N52 with ESS SC, catless headers and 3IM-
4.50" 115mm pulley makes 5psi boost at 7000rpm.
It is predicted based on linear boost curve that with-
4.25" 108mm pulley will make 5.5psi at 7000rpm, +0.5 pounds of boost.
3.80" 96.5mm pulley will make 6.0psi at 7000rpm, +1.0 pounds of boost.
3.40" 86.4mm pulley will make 7.0psi at 7000rpm, +2.0 pounds of boost.