I currently have dual flowmaster super 40's installed that come out the corners of the rear bumper. I've had it on for about 6 months and have recently decided to change it up a bit so I got 2 hooker aero chamber mufflers, 2 magnaflow hi-flo cats, DT long tubes and rear o2 sims. My intention is to dump the exahust right before the rear axle. My questions are how involved will it be to exchange the headers? And I was told I need o2 extensions for the front sensors...I called URD and they had said I can just put them in the port is that true? Any help would be appreciated!