wish i knew about the part numbers before i replaced my plugs.on the serious note what is exactly is the worst possible outcome of not choosing the best plugs around.from what i read,im guessing a decrease in gas mileage.i went with bosch platinum +4 and it terms of performance i didn't really notice anything.i thought i heard misfires at first but then i got the codes and the only one that issstill outstanding is p0174"system lean".vaccum hose leak or 02 sensor most likely.fuel delivery problem at the worst.ive had that code for a while now and im not too worried about it