As long as it sounds like
THIS it`s the waste gate opening. Your hearing it now as the new turbo even though not mapped is making more boost which makes more noise when the waste gate opens. Your running about 1.6 bar peak at the moment. You should have come for a ride in my car when it was running 2.2bar peak new rebuild hopefully running 3 bar peak.
Turbo compressor surge sounds the same but is totally different thing which you don`t want to hear your turbo doing as
HERE .