Please read this nice test...
http://www.bobistheoilguy.com/airfilter/airtest1.htm
With K&N your engine becomes a s%it sucker!!!
The best filter is the stock or a good paper filter when new.
But the paper filter become dirty soon, you can spry with air once or twice but before one year of continuous use you've to change it.
The better filtering/performance balance filter is the UNI foam filter. Keep clean and oiled and it's the cheapest and better for your engine life.
