Steve,
several years ago, one of the forensic engineers who is also a member of International Automotive Technicians Union(IATN) posted an analysis of filters available, who made them, quality of construction, etc. I don't think he compiled it, but it came from someone who did a lot of research.
K&N is manufactured by Wix, who also makes Napa Gold, and a couple of others. Can't remember the name of the other manufacturer who got top marks, but it was an agricultural type name.
He also did breakdowns on oils and a later post on antifreezes and brake fluids.
ZDDP was taken out of API rated oils by political manuvering of the auto manufacturers so as to preserve the life time of catalytic convertors. You'll find that the European oil manufacturers did not follow suit(they are doing so now, but slowly). Any oil that is rated after SJ has almost NO ZDDP. Has to be free to be rated by the API(Automotive Petroleum Institute). I recommend Yamaha or any other motorcycle oil that is still rated SG or SH. Those oils have the best "protection package" of additives in them. Or if you're travelling to Europe, buy their oil and ship it home. Over here in the middle of the Pacific we have not encountered(that I know of) the DAE oil. And I am fairly well up on the chemical/petroleums available here.