Cat pipes are extremely illegal because you are removing the biggest part of the emissions system (you know how people are these days...), but will not throw a check engine light as the oxygen sensor is up stream of the cat. If you have a shop make you a cat pipe, do not tell them what it's for, or they simply won't make it. Just tell them the size of pipe and the 2 bolt flanges, as well as the angles that they are positioned at. Unlike most rigs, the Pathfinder's cat flanges are not perfectly horizontal they are like / in the front and \ in the rear. If you truck was ran really rich at all, your cat is most likely somewhat clogged. After my Coolant Temp Sensor on my old '87 went out and dumped a bunch of gas in, the thing would not move. Almost no power, flooring it barely did anything, could not accelerate barely, etc. A Magnaflow high-flow cat cleared that up and gave a big improvement over stock and a good fuel mileage increase.