Instruct: Classify Amazon reviews into positive or negative sentiment
Query: IMPRESSIVE SPARK PLUG!

I decided to replace these due to the mileage and the fact that I was also replacing the wires.When you have old spark plugs out, these is an opportunity to see how each cylinder is burning by the color and condition of the electrodes. I can't believe the electrodes were still visible, gotta love that Iridium!! The color of the plugs were normal, so since I had them out I replaced them.Great plugs!!