The standard OCI is 7,500 miles. With regard to filters, on our '06 Aero I use the Fram PH9715 (Subaru-specific) and have never once found an issue with the ones I've cut open.
Some here may disagree, but one other suggestion I have is to forego 5W-30 for something a bit heavier. I primarily use HDEOs in ours - currently 15W-40 Rotella T for the summer. You'll note that the owners manual actually recommends the following viscosities for high temperatures or "heavy-duty" usage: SAE 30, 40, 10W-50, 20W-40, 20W-50.