Wondering if fram's extend guard, or tough guards are any good? Ive done alot of reading here, and msot seem to say adn think, the extend guards are really good! Not all though. I read the oil filter study here, and the page listed the tough guard as being and excellent filter as well. I normally use pureolator pure one, and Mobil 1 filters for finer filtering. Was considering trying a K&N for the colder winter months. Whats everyone's fact, or opinion?