200q Boost down!!

[SOP8920@Siena.edu]

Hi folks,
   Okay.. I'm getting closer to the mystery now. It looks like my drivetrain
problem is boost related. I'm guessing I have a boost leak somewhere.
Here is the symptoms: When winding it out, I'll here a metallic whine at high
rpms and when clutch is depressed. Also, the boost guage is no longer reading
as high as before. I can't give you an accurate read-out of the boost pressure
at this time because I've had a chip/boost mod done and the dash-reading is
wrong. However, when everything was tip-top.. I was getting a solid 1.4 rather
quickly. Now, even under the hardest throttle application, the boost will read
only 1.1. All I can say is HELP!

How should i go about diagnosing the problem? Anywhere to start? Any idea how
expensive this is gonna get? Thanks
                               -Osman Parvez
                                89 200q (160K miles)
                                Siena College
                                Albany NY