How does boost pressure work on a focus St?

This may sound harsh, but that's how it works on the Focus ST. Boost pressure on the small stock turbo falls off hard towards redline dropping as low as 10psi (keep in mind I am doing this testing at over 5000ft asl). When you tighten up the preload on the factory actuator, you can maintain a little more boost on the top end.

How much BHP does the St focus stock Turbo have?

It is well known that the ST Focus Stock turbo is max'd out at 320-322 bhp so any gains above this threshold are going to be quite small unless the Larger RS350 Hybrid turbo is used. So what have we done to release the extra 10 bhp without the Hybrid 350RS Turbo?

How much psi does boost Guage drop?

About a 20% drop. Also noted that boost pressure wont go beyond 3/4 on the boost guage. when running thru first and second under a heavy load, boost was about 18 psi. also the same in a push on the interstate from 50 to 80 in sixth gear. I'm wondering if I am loosing boost pressure. don't hear any whistling sound like a loose turbo tube.