ive read ALOT about oil fitlers! what ide like to know is, theirs always talk about how well a fitler flows, and restricts. example, purolator pure one, is notorious for being restrictive... their premium plus is dman good, if not the best for full flow. my car didnt run as good with pureone, but ran like a bat outta **** with the premim plus. what is it, with the oil in the filter, that makes it full flowing, and restrictive? thickness of the media? filter design? how well it is fitlering and letting the oil back into the engine?