well there seems to be some crackling noise in the passenger door it sounds like. i would say that it must be the speakers not being properly grounded. but it only happens when it's cool/cold and when i go around 40+mph. i took it to performance nissan and they told me it was a loose panel...they tightened every bolt but the sound is back. it can get really loud sometimes and quite annoying. does anyone have a solution or probably a fix to this problem?