Today I was driving fast for several minutes, wanted to test with forester 2001 y. (he was faster a bit, both stock) and after that the strange noise is gone and some other kind of a noise is heard that is not dependent with boost, at any rpm, even when pushing the gas pedal very nice it sounds like something coming from down, propably pipes, just like something is not screwed well, but the sound is off when I take of the foot from gas.
Except that I noticed a little leakage of oil on turbo to TMIC hose, and the smoke was coming from down, seems the oil has leaked on hot pipe.