I work @ an Auto parts store and have cut open nearly every filter we stock, and i can tell you there is distinct differences between most them inside, so i have to dissagree on the simple "canister swap" conclusion ;)
As for oil itself, better watch out guys. the standards are killing off zinc rich oils and you start running an oil with less than tolarable zinc content no matter whos names on the bottle (theyre ALL doing it), kiss your camshafts and engines goodbye :(