Review on K&N HP-7002 Oil Filter | High Performance Filter for Enhanced Engine Optimization by Jason Yancy

I have used this on my Volvo S80 and XC70. I noticed that my average highway mileage improved a few mpg on the S80 - 28. I didn't notice any impact on city mileage. Overall a quality filter for less than $[.] at amazon.com. The few bucks more definitely translates into fuel savings over [.]$ OEM Mann/Mahle, although I would change the oil at the same interval (I change every 5,000 - Volvo recommends 7.5,000). I think Champs or Mobil One filters are better at extending oil life with better filtration based on oil color at 5K, but give less flow and around the same MPGs as OEM. I assume that the high-flow claim of K&N filters is correct. Update 8/4/2009: I saw this much more scientific review of the K&N filter on the Volvospeed website. I was very surprised to see that my generalized assumptions had some basis.[.]