I've updated my site with filter areas. Nothing too suprising, the Fram was the worst, Purolator was the best. It did shed some light on filter construction though. Most filters held up well after cutting out a center strip of paper. The Fram however was completely destroyed. As soon as the filter material is damaged, the cartridge looses it's structure, and more easily be damaged further.
http://www.lesabret.com/filters/filter.html
-T
http://www.lesabret.com/filters/filter.html
-T