Boost leak question

[DerekK]

I have a sps62. I hear a sound that proved to be a boost leak on my last set up. Normal turbo wistle, then it hits 30psi and I hear a secondary whistle. I have inspected, and replaced all boots, pulled the intercooler and checked for imperfections in the metal. I have even sanded the intakes on the intercooler for a very smooth seal. The only thing left is the turbo. I have not been in another truck with this turbo and I do not know if this sound is normal. The allen screw in the brass 90 is as tight as it can get and the turbo is peaking out at 41psi. Could it be leaking at the waste gate. I checked the blue hose from the 90 to the waste gate and it seems to be secure. I have no condensation evidence around the turbo from a cold leak, but between the sound and the fact that i thought this turbo would produce a little more boost with the allen adjustment tightened flat leads me to believe I have a leak somewhere. Any help or insight would be greatly apprieciated.