Well I've been using it now for over 2 weeks and the only difference I've seen is a slight increase in throttle response and the noise from the engine area. I'm not getting better gas mileage yet but that could actually be my fault. Overall I'm happy with the purchase, arrived quickly, good fit and finish and installs easy. I've had one in all of my vehicles and will continue to buy AEM filters until they don't make them anymore. Good buy!