Be careful buying parts on Ebay or Amazon--depending on the seller/supplier, there have been tons of fake Chinese counterfeit parts sold there, especially filters and tuneup parts--the parts and boxes appear to be the real thing unless you hold the authentic part right next to it.
I have not heard of any such problems with RockAuto, and parts stores (O'Reilly, Advance, AutoZone, etc.) and of course, your dealer service dept., should all be safe.
Caveat emptor.