Hey folks! Allow me to introduce myself. I've been the owner of a 2010 WRX since late April. Dealing with the oil consumption, it's been a fantastic car. Until recently anyways. Which is part of the reason I'm here. To learn! My other vehicle is a 2008 Buell 1125R. It didn't get much riding this year though. I worked out of town too much. Anyways, glad to be here!
3" catless TBE, uppipe (I think), Grimmspeed AOS, tune. The only things I did to it was a custom axle-back and the AOS. The rest was done by the previous owner. He jacked up the PCV system so I tried to fix it and put the AOS on.
I would try to un-fark the PCV system and get rid of the AOS and see if the problem goes away. I've seen people with catch can systems run into problems with burning oil. Don't ask me why that would happen. But I believe 6MTizzle had that issue. PM'ing him will get you nowhere though as he doesnt' visit here anymore. But when he's over at my place again (probably next wednesday or thursday) I'll ask him what happened. Personally, that's the only thing in the system that I can think of that would affect oil consumption, other than blow by past the rings and the normal culprits. But your other mods don't really strike me as oil burners.
Yeah, the oil consumption has been pretty steady at 1qt every 1k since I bought it, before and after the AOS. But yes, the PCV has always been messed up. I think the real culprit now is either a toasted turbo or ringlands... I'm getting a compression test and stuff done today and talked to Nuke last night about fixing the problem once I know what it is.
Good luck sourcing the problem! I was burning a quart/1000 miles in my hybrid 2.0/2.5 also. The 2.5L was a brand new 2010 block from Morries. Welcome to MnSubaru!