Everyone thinks in terms of an intercooler causing a "drop" in pressure due to a restriction in the manifold. This is only partly true... there is also a reduction in volumn of air and gas due to the condensing of the mixture... cooler air takes up less space than hot air... hence less pressure. So even if there is no restriction from the intercooler (low speed, low engine rpms), you will see a drop in pressure under the intercooler. Keep in mind that the denser the mixture... more is going into the cylinders. So what I'm trying to say is..... forget about pressure numbers and see what the engine will do on a dyno with different pulleys.Just use the boost numbers as a guide line... Keep constant monitoring of the ex gas temp and any signs of detonation. Remember.... the air will condense more than the fuel... so you have to adjust the mixture accordingly. After the initial dyno run.. look at the plugs and see what the mixture looks like... Engine R and D takes lots of time and money on a dyno, but saves lots of money in blown up engines and burned through pistons.