I'm so happy - our neighbour has been threatening dire consequences if we proceed with getting an en-suite shower installed on our side of her bedroom wall.
I even went and bought the newspaper, thus making a hypocrite of myself for spending money on INM product.
Note that some power showers are extremely noisy, and if it was on the other side of her bedroom wall and you were showering at odd times, could have a serious on-going negative impact on her life.
I'd suggest for neighbourly harmony that you would think of placing it on another wall (not directly onto her bedroom).
Sound proofing in new builds seems to be very bad in my experience and I can hear my next door neighbours shower and extractor fan. Very annoying. We had no choice on where to locate our electric showers but if we did I would most cetainly choose an option which would have the least impact on neighbours.
If you can hear them they can hear you, so it works both ways i think. If the option to have a shower placed where the sound is minimialized then it suits both parties!