I had a noise coming from my dash and/or MFD, and was finally able to fix it, but you might not like the solution:
First, I took it to the dealer and had them check it out. It seemed to be coming from the center of the dash, and would go away if I pressed down on the MFD and/or dash. After I picked it up, it got better but didn't go away. I eventually discovered that they added tape (crappy foam tape double-sided tape, by the way) to the inside of the cover of the defrost vent. They had me pick it up, and said it was fixed. It wasn't.
I then gave it a go myself, and disassembled the entire MFD, which would squeak if I put any pressure at all on it. I applied 3M friction tape, which is awesome stuff, to any and all possible contact points. You have to get creative around some spots, because you want it all to still fit back together snugly. That eliminated any and all noise from the MFD.
But...the noise was still there!!!
I tried lots of stuff at this point. I re-taped the defrost vent, adding more than was there. I shoved a pair of undies under the defrost vent, which really seemed to be the source at this point, but I simply couldn't get enough compression in there from underneath to keep it from making a little clicking noise when flexing it back and forth. I wasn't crazy about pulling my whole dash off to get underneath, but if I pressed down on the dash, there's no noise...
So...finally...here's what worked: I bought a piece of 5/8" black nylon rope from HD, cut it to match the length of my dash, and carefully wedged it in between my dash and windshield, covering up the little bit of foam that's existing. It's a tight fit over the speaker grilles, but was the perfect size.
The noise is gone. I can't even force it to come back if I try flexing the dash like before.
The black nylon rope blends in surprisingly well.
In the days since this solution, I have fallen completely in love with my Forester all over again. I haven't even had the radio on because I love how quiet it is now.