I have a little problem. is that the car has a little hiss or pressure leak is heard separate the turbo starts to blow or run.

I changed:
All vacuum tubes and pressure / depression of the vehicle or I think they are all.
I have also checked all the intercooler hoses and I've changed.

The only thing I have noticed that bad, are the studs and exhaust manifold nuts that there are 2 that are about the past and not loosen or tighten. Can whistle or lose pressure for the exhaust manifold the car?

Arto something I already know what else I can not watch.
"Exhaust manifold broken or bent? Any leak or crack?

The turbo has 20 000km and has always been perfect.