I'm wondering if I got the wrong plugs! I went Advanced and I told the guy I was on a budget. Now I'm no ASE mechanic (but not affraid to get dirty), and I do ask a sh*t load of questions before I do any work on my 2003 GT. So when I went to Advanced they gave me Champion copper plugs....I just replaced my Cat, plugs and wires. I got Autolite "professional" wires, and those champion plugs. When I accelerate I can hear a faint knocking and I'm not sure If I should replace my plugs AGAIN!!!!! I only hear it when I hit the gas. Also does anyone know if using a magnaflow cat (direct fit) is louder at the top! Or am I just an idiot and screwed something up! It's much louder than it used to be. There is something at the top of the down pipe (which wasn't on my stock cat. Just wondering!!!!
