I'm swapping my K&N air filter for an Amsoil (model # TS115 according to the Amsoil product application guide). Anyone who has researched K&N filters to any extent is aware that they improve flow at the expense of filtration. There is a trade off for the performance increase; dirt in your engine! I've always used a K&N but have been uneasy with the trade off. I've even considered going back to paper filters on several occasions, especially after finding dirt behind my filter!

I'm wary enough of my K&N to try the Amsoil. If anyone has had bad experiences with Amsoil air filters let me know.

By the way, I'm aware that the graph from the Amsoil site is idiotic in it's execution. I'm hoping bad graphic design doesn't equate to bad air filtration...

From the Amsoil web site
  The Amsoil is cheaper, apparently flows just as well, and, most importantly, claims to filter better.

Check out these links:

This, from Gadgets web site, doesn't address the filtration in any scientific way but dyno tested performance...

This is from Barney M.'s archive of Toy4x4 list serve threads. It recounts the oft cited, but poorly documented, story of the maintenance supervisor at a large mining operation who tested a variety of air filter types "using SAE J726C Test Method" and appears to systematically address the filtration issue.

This is from a multilevel Amsoil dealer but also appears to systematically address the filtration issue.

Go to Amsoil's site for a product description or order online.

 The filter is a dark foam with a sheen from being pre oiled for use right out of the package.

A close up of the filter media shows the 2-stage construction with a more open foam providing pre filtering and denser foam for finer particles.

 From the back you can see the metal structure that insures the filter holds it's shape.