I have a 2011 legacy 3.6r
I have a 2011 legacy 3.6r with 105k miles. I have used mobil 1(just the regular stuff), castrol gtx synthetic and penzoil platinum all 5w30 and it consumed oil only .5qt per oil change on the mobile one. The others it has not consumed anything. I just bought a 2017 outback 2.5i in december that uses 0w20 and i have not seen it consume oil yet. I put the same 0w20 penzoil platinum in it so we will see. I also change the oil every 4k miles. 6k is too long for the small subaru filters. Plus i use purulator filters anyways. They are top tier and the same price as oem.