the evidence so far is lack of a proper data sample, meaning that even just in your case alone ,you can't come to a conclusion until you've driven at least an equal amount of miles on the napa ones, and like i said in the above post for all i know the napa ones could in fact be exact spec oem ones just re-badged, or they could not be, i've never seen one so i don't know, i would want to fully check one out first or if i had a little extra money in my pocket just buy oem and forget about it, point is in reguards to your post above, i can;t prove the napa ones are not as good and you can't prove they are as good at this point, lack of evidence is not proof and conversely lack of proof is not evidence for debate. right now, without trying to sound like a douche we're "argumentum ad ignorantiam" or arguing from ignorance.
Argument from ignorance - Wikipedia, the free encyclopedia
neither one of us can be sure at this point and are arguing something we don't really believe in or know the answer to, haha
anyways, like i said above though, don;t care if it's the same part built to the same spec from the same materials, then who cares what name is on the box, i'm just not sure that's 100% the case yet, until i see the part for myself and compare against an oem one.