I orderd a White Brothers E-Series Exhaust for my 01 250ex. It came with a White Brothers Powerfilter. I was originally going to buy a K&N filter but since I got the powerfilter, I decided just to throw that in. Is a K&N filter better or are they both the same? Will i see a horsepower diffence if I go with the K&N?

 

The K&N will flow better and you might feel a little more power difference if any. The Powerfilter is better than the stock one and is still safer to use than a K&N. I've had both. I like the K&N better for performance reasons but it requires maintance more often.

 

I ran K&N for years, but have now gone back to UNI foam. (I am pretty sure UNI makes the Powerfilters for WB.) My advice is to play it safe and stick with foam! A good quality foam filter flows almost as well as a K&N and offers a lot more protection.

 

Yep If I could do it over I would go with Uni also. I will on my next airbox.

As far as HP gains from K&N..its alot of BS...I couldnt tell a darn bit of difference between K&N and my stock foam filter.