Hyteck9,
I bought a brand new '05 Legacy GT 5 sp Wagon on New Years Eve that is exhibiting the same exact symptoms that you describe. I just flipped 1000 miles today and use nothing but 92 octane (the highest you can get in NE without going to the race track). Since I now know that it is not just me, I am going to go talk to the dealer and see what they can do. Let me know if you come up with a solution on your end.
Van1