FYI, I posted a video in your thread by two physical therapists explaining what you are likely experiencing on your Prius test drives. Their fix is not so pretty and I'm still working on a decent fix also,
Thank you, I watched it. I still want a Prius, but don't want to have to deal with foam wedges, cushions, and a bad back, so have to test out that power seat before I can decide. If not, maybe they will fix this in the new upcoming generation. I need a car before then, though, so it'd have to be a car I own in the future in that case.