Re: 2008 STi - Broken welds on rear roof support (metal on metal squeak)...
+1. I'm of the opinion (it's my experience) you only have a certain amount of rope with most dealers, so choose wisely when you decide to use that rope. I suspect you're nearing the end of the rope here, so rather than push it to a point of "pain" for the dealer (which may affect/influence how you're treated in the future) chalk it up to experience and move on. Keep in mind it's not unusual that fixing one noise/squeak can lead to 2 more new ones...I'll probably get flamed for this but here goes... I don't really think the dealer owes you anything. Yes the squeak was mis-diagnosed but the whole car is metal which can cause the noise to sound like it was coming from anywhere. For example, ever tried to diagnose a squeak on an aluminum framed mountain bike? It's pretty much impossible. You were continually pushing the dealer to provide a solution so they were taking their best shot at what they thought the problem was. Most dealerships I know would have just jiggled around some stuff and told you they couldn't find it and to deal with it. Admittedly it sounds like their techs could use some classes on problem solving but it's not like they threw some glue on it and said they fixed it. They genuinely gave it a shot at fixing it.
I understand you're frustrated with having to be without your car for weeks at a time but lets face it... it's a 15k dollar car with 20k worth of drivetrain in it. It's never going to be as quiet and rattle-proof as a pricier car like a BMW, MB, etc.
Cliffnotes: I think the dealership took their best shot at repairing it and you should give them credit for footing that huge bill when they could have just told you to shove it. Get them to fix the hatch supports and call it a day.