With a quick call to MagnaFlow Exhaust we had a 2.25-inch stainless steel Hot-Rod Builder Kit (PN 10701), a stainless 5x8x14-inch oval muffler with offset/centered 2.25-inch inlet/outlet (PN 12225), and a Universal high-flow catalytic converter (PN 99036HM) to tuck up under the little CJ and quiet that 2.5L down a bit. Yep, we added a Cat on an emissions exempt vehicle. Why? Well the ’98 XJ computer has an upstream O2 sensor and a downstream O2 sensor. Running no cat might cause the engine to run funny…or at least smell funny.