Nothing can compare airflow of a new, clean paper filter, not even K&N, they admitted this fact themselves..!!
So if it's REAL performance you're after, stick to the factory filter, and maybe change it a bit more often.
(On the other hand, if you're driving a big, carburetor equipped V-8 in dusty desserts, you may need K&N...cause that's what K&N is designed for in the first place, in our cars, it brings nothing but noise, complete waste of money)