Okay, so I broke down and got the Mac Longtubes. I'm getting the SCT XCal2, so do I need extensions for the front 02 sensors? My complete setup is Mac Longtubes to a custom O/R H-pipe to mufflers then to the tips. I know the XCal2 takes care of the light the engine throws without cats, but do I need to put the extensions to put the sensors on the headers? Thanks.

 

yes, the extentions are for the fronts, they HAVE to go in becuase they control how your car runs. the rears are the ones that the tuner shuts off.