The high pitch noise you hear is the turbo spinning. This is normal given the intake kit you have installed.
How is your boost guage installed? Given that you have the boost controller also I doubt that your wastegate is opening early or stuck open. If the controller was intalled properly and still working, a stuck wastegate wouldn't matter.
How does the car run?

__________________
'85 300SD (formerly california emissions)
'08 Chevy Tahoe
'93 Ducati 900 SS
'79 Kawasaki KZ 650
'86 Kawasaki KX 250
'88 Kawasaki KDX200
'71 Hodaka Ace 100
'72 Triumph T100R