FYI if your looking to add or remove any such components mentioned little to no increase in sound can be had with the oem setup,the true bottleneck is the oem DP's,the 3rd cat or resonator is not as restrictive as many might think,IMO if your looking to add some additional sound think you will be better off by adding an aftermarket intake such as the MDesign CAI or Airaid,think he has a special going on at the moment. Z