Problem with the turbos or the filter

[Lual]

Hi, My E70 3.0 SD with 200.000 km has an issue revving up. Many times when pushing down the pedal the car hardly revs up, and it does it only when fully pushing down the kick down.

One BMW garage told me it was a problem of the particles filter. Another one told me it is a problem with one if the turbos (the one revving at low rpm).

Any body having experienced the same problem or having a clue?

Thanks