You keep bringing up interesting facts and not explaining them.
So again I ask, what does any of this mean?

(1) No, it does not have an anti drain-back valve. The oil filter hangs upside down, which means that oil can not drain out of it. Therefore, having a valve that would prevent the oil from draining out is redundant and pointless. The oil passages downstream of the filter could indeed drain back into the filter, like a full straw draining into a cup it was lifted out of. I suppose if my car rolls over it might become an issue, but I'll deal with that one when the time comes.

(2) Too close for what? This statement implies that the filter is somehow closer to the manifold or that the exhaust manifold is somehow different between the 2.0L and 2.5L motors. It's not, they are exactly the same size and shape. The filter sits in the same place on both motors, and from my measurements with an IR thermometer the two cans were within 5*F of each other after a "spirited" 45 minute drive.

(3) That Napa Gold filter is what the book at the auto store told me would fit my car, which is all most people bother to check before installing one. Not that it (bypass pressure) matters at all. My point is the bigger filter, which by the way has the correct 20-25psi bypass, is better.

 

PL14612 is for both 2.5L and 2.0L turbo GD chassis Subarus. PL14615 is for turbo GR chassis Subarus.

Specifications:
Anti-Drain Back Valve Yes Height 2.93
O.D. 2.69 Relief Valve P.S.I. 14-18
Threads M20-1.5 Type of Filter Spin-on

Not enough research and data collection has been done to prove if running 18psi vs 22psi has lead to any issues.

Current blue Subaru filters are made by Honeywell which manufactures Fram filters in Canada which have been known to have terrible filtering properties.

Purolator is owned and manufactured by Bosch.

 

It seems you're pretty set on using the same oil filter, so after this, I'm done explaining your fallacies. My original post was just to say you're comparing apples to oranges, but you asked "what does it mean?" I'm not sure how else to explain you're comparing apples to oranges other than the PL14460 was to clear ALL 2.0L motors and the smaller more compact style filters are designed to clear ALL 2.5L motors.


1) Partially correct. However, it's not the only thing an Anti-drainback valve does. Using your straw comparison, if nothing is happening the water level of a straw will be the exact same of whatever it's sitting in. However, if the water line in the straw is higher than the cup it's in (like when the oil pump is pumping oil), once all outside forces stop, the water will drain back from the straw into the cup until they reach equilibrium. This can reverse flow back into the sump and also there is more volume that needs to be refilled with oil post filter. Again, as I posted earlier, you can determine if you care, because this topic is very debatable.

2) Again, only partially correct. The 2.5L STi exhaust manifolds are the same as the 2.0L engines, however, the 2.5L WRX exhaust manifolds are different. That is, until they completely changed the chassis design. So, no, not all 2.0L and 2.5L exhaust manifolds are the same.

3) Just because it fits, does not mean it's the best part. The 57712 Napa Gold filter, as far as I can tell, was introduced approximately early 2012. Why not use the filter that meets all OEM specs instead of some?