After I read the last post from leedsquietman I checked it again - and this time I did it carefully.
- in track 1&2 is the same files
- file tempo = track tempo
- second file has an inverted phase
- first track is in repitch mode, second in complex.
- I had to add 2 samples delay for best possible cancellation (reference to my last post)
artefacts ca. at - 40 db

conclusion:
yes, complex does alter the audio.