hmmm...

ok what you need to do is compair vacume readings before and after the different filters, that way its not subjective...

now I fully believe that you can feel diferences (wont go into the playing i have done with the intake on a 940t) but fact is fact the ONLY way to get a engien to breath better is to remove restrictions from the air inlet (hence a clean filter breathes better than dirty one..less restriction, However (weirdly) a dirty (paper) filter (to a point) also FILTERS better (holes blocked with dirt are smalelr holes, hence trap smaller particles...)

so basically an engine that breathes better swallows more dirt and has shorter life....now the question is where the pivot point is in the filter arrangement that gives good breathing WITHOUT shortening the life too much..and i would imagine where you live has a bearing (lets say your local road was covered in powdered carburundum dust you REALLY would want the best filtration...)

it really is a case of you pays your money and you takes your choice...but look at removing wire screens from MAF and straightening elbows in pipes for a better (and safer) gain...alterantively wind the boost up, take the filters out, run 6" pipes and call it dragster :-) (oh and engine rebuilds very frequently so who cares about the air !)