I'm not quite sure how to describe this, but on most cars, I'm used to the wiper blade being dragged across the windshield, then when the arm reverses, the blade flops over and is dragged back. On my Boxster, the blades don't flop over - the arms drag in one direction and push them the other direction. It's when they're being pushed across the windshield that they squeak so badly.
Is this the way it's s'posed to be? (And is my description making any sense whatsoever?)
(I did see RandallNeighbour's suggestion for using FK1-425 on the windshield to reduce the squeak and am trying that, but am still wondering about the wiper action).