The 03-04 models have no cat on the bottom only the muffler, unless you have the califorina special. The 04.5+ have a cat on the bottom.
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-03' 5.9L w/Edge Mileage Max, 4" TBE, GHD, Modular Intake, Boost elbow
-85" Mustang GT CFI
-70" 440+6 Challenger R/T