I just had my gibson exhaust installed but i think the muffler shop only took from the muffler down to the exhaust outlet and replace it with a gibson muffler and a 3" pipe and weld nice exhaust tip on the end. my question is should they also change the pipe from the catalyc converter or also change the cat converter? the gibson exhaust sounds really nice and you can barely notice it when the Armada is idling.