[Brock]

the K&N relies on oil to catch small particals because of their more open design for high flow. the amsoil has an external microfiber that catches the small particles and then has their high flow internally. Two different ways of doing the same thing. I am sure there are more differences but that is the main thing.

you have to buy them through a local dealer or go to someones website...either AMSOILS or a dealers such as mine that is linked below.

As for oil change intervals.....oil intervals at 3k miles were based on oil and filter technology of decades ago. The synthetic does not break down and lose viscosity and cleaning properties due to heat and such like regular dino oil. BMW uses 8000 miles on my wifes car.... If you send your oil for analysis and it is not showing abnormal wear and is still lubricating and protecting against heat shear then you can go longer. By all means change it sooner if that is your comfort level...all I know is that with true synthetics and high quality filters you can go much longer. send me a pm with your email and i will send you some documents.....but in the end it is up to you.