So the filter the Subaru parts dept would sell me for my 03 Legacy would be a different model with the correct bypass setting than this one sold at Walmart?Yes it will fit but the bypass setting may be too high. The Wix cross for the -20A part lists 27psid for this newer filter, The old filter for your 2003 EJ253 was 23psig +/-
Though it would "screw on" and likely not leak, I would not run this filter on your 2003 Legacy vehicle.
And unless you Nephew is experienced with the "challenging" Subaru EJ oil changes - I would go to the dealer and pay the extra cash.
Had you been using a cup wrench to extract the filter from the encircled converter heat shields ?
The Wix is the best filter for it?
My nephew has had a couple of WRX’s and used to work on my Uncle’s several Subaru’s which included a few EJ engines.
I’ve owned 10 Subaru’s over the years with most of them EJ engines. What is challenging about changing the oil on them?