I noticed a 10-15F degree change in ambient temperature reduced my gas mileage significantly.so I bought this car with the MANN filter, which has some weird soft stuff that actually helps prevent pollen and dust from entering air chamber. I just installed the K and N drop in air filter. I immediately see better results in performance and even gas mileage 3 mpg increase. Is there harm in using the K and N over the MANN that helps prevent more tiny particles from entering. Which is best to keep my car running smooth for the long run?