Boost is faulty and car down on power

Is the MIL indicating?
Check for leaking hoses between the turbo and engine. If no leakages found, check the turbo unit for failure.

This is a simple system to diagnose... but not so easy to explain over
the internet / via a keyboard.

First, you need to make sure that the intake manifold is not plugged
up... causing lack of air to enter the engine.

Remove elbow hose at the top of the engine to have a look...

If the intake is clear, you need to check for proper movement of the
turbo vane actuator / rod (at the back of the engine, best viewed
from under the engine/car).

http://www.youtube.com/watch?v=cGRsgYAE-CI

As soon as the engine is started, the actuator rod should be "pulled down"
which causes the turbo to spin faster (boosts quickly).

Once the engine computer measures enough boost, the rod is released
which slows the turbo spinning / lowers boost.

When the vanes get "stuck", the turbo does not spool quickly and
the engine feels low on boost.

When the actuator rod does not move... the "vacuum source" to the
actuator pod is bad (low vacuum, broken vacuum hose), the vacuum
solenoid is bad, the actuator is broken, or the vanes are stuck.

Thomas