Thanks man that is a huge help! It is much appreciated. I think I have the same problem as you, no apparent leaks but intermittent problems that seem to be getting worse. I think there may be a leak behind the pump that's out of view since I have a little fluid on the block. Thought it was just a little bit from where I replaced the inlet o-ring but it's never dried up.
I hope I can get this thing fixed. Driving an STi without power steering is neither fun nor easy. If it was just dead completely it'd be manageable but it wants to cut in and out at the worst possible times like sharp turns and parking lots.