Also, I have found that the low-noise props have made ZERO difference on my P4P. I had one P4P flying right next to another. One with low-noise props and one without. I could not tell the difference. It seems that you can indeed pick up a slight difference with a sound meter, but nothing that I could tell with my ears.
The noise with 'low noise prop' is less disturbing for somebody - lower noise but almost no difference in volume.
The thrust force is almost the same. I unintentionally attached one original prop with three LN prop some day. The flight was normal just maybe a different sound.