Just changed oil this past weekend with Mobil 1 0-20W from walmart. No problems here. Mileage is 1200.
Got my filters here: http://www.subarugenuineparts.com/pr...oducts_id=1898
my take is: mobil 1 has been around for a long time and is highly regarded by people. I care for my car just as much as the next person, but since i'm doing 5k intervals, it shouldn't have any problems since i'm changing it so often vs 7.5k or even 10k others are doing. Just my opinion.