Casey, With your new air box along with my tune up kit and new 18,000 volt coil kit. I might take the car to a shop here in Dallas and check it out. There has to be some kind of a difference. Wheather is low end or high end. I see a difference with the coil kit in passing and loading up the system when you floor it. Bosch even advertises a better performance with the platinum 4 + 4 plugs. That's what I use. John www.specialTauto.com