Most cars have magnets on the oil plugs (stock oil plugs anyways). I think they put the magnets in the pans to try to catch the metal particulates before they get to the filter, because the filter should catch them anyways.
I read through that website. Think who ever wrote it just was over thinking the issues.
The filter is meant to stop metal and other larger material from damaging the rest of the engine. A few magnets here and there just are over kill and wont add life to the oil or the filter.
I see it as a waste of time.
Plus i am pretty sure if he knew what he was talking about, he would of gone on about beta ratios instead of filters sizes.
If the motor oil being used in an engine is lubricating so poorly that it is allowing excessive wear metals to get into the oil, the problem isn’t a magnet or not, it’s the oil!
Use better quality synthetic oils to rectify this problem.