Ok I purchased a cold air from ebay a year ago and was satisfied with it. It was loud and had a deep tone but as I started the car this morning it seemed fine and was just cruising to school and I entered the highway and pushed it a bit and it was real loud. It seems more responsive now, and real louder than what it sounded before, unsure if this is normal and also you can hear the intake deep tone when im on 3500 and going up. I know my filter is a bit rusted and haven't changed it since but is this normal?lol but it does sound better lol