If you want a K&N, Alba has a nice setup:
http://alba.buyol.com/Group/99MP96CHUXDEOFIV.htm

Vent your airbox lid too (if you aren't running in real wet conditions). That alone will make a huge difference!
http://www.ehsracing.com/

You will need to rejet!

If you just want to get a foam filter that is better than stock, try Uni (http://www.unifilter.com/) or White Bros.

I have been using the Alba setup, but am in the process of changing from a K&N to a foam filter. I will keep the (trick!) Alba adapter, and put a Uni Universal foam filter (#UP4300AST) on the Alba adapter.

 

That alba setup looks good but i never no when i will be running in wet conditions