I just got my car smogged last week, and thank the car gods for that one! Usually it's a pain to get my car smogged. This shop was recommended to me from a muffler guy and said this shop will smog my car for the car that it is and not worry about aftermarket junk. He was right. The guy even asked me, "so you install these headers and do the engine work yourself?" alot inside my engine bay is painted red/black and I have pacesetter headers and a K/N cone filter and he didn't even say they weren't street legal...
...anyways, as he was smogging it at 2500rpm I noticed it was misfiring, I hadn't heard it before cause at idle it's fine and being inside my car and driving I couldn't ever tell. It was misfiring bad and I asked the guy "you hear that misfiring? what do you recommend I check to find out what's causing that". He said "check your distributor cap first, it's easiest, that's most likely the problem, if not could be the plugs or possibly wires. are you using bosch plugs?" I said yes. he was like "take them out now, those are crap, I used to work at Saturn and when a car didn't pass 90% of the time they were running bosch".
So very soon I'm going to go get some of those copper NGK's, just gotta find them. It's not hard to change plugs once a year anyways.