Denso Iridium Spark Plugs on 2003 Corolla S

[quadophile]

I bought the 2003 Corolla S back in October 2008 with 99,965 miles on it. Now after 18,000 miles have so far been added I was curious about the plug condition. I pulled one of the plugs and decided to replace them. The ones installed were the NGK Iridium. I replaced them with Denso Iridium IK16 (5303) yesterday.

After the change which went without any issues I went out for a spin. My thoughts on what I felt before and after the change:

• A wee bit more power/acceleration
• Much smoother idling

I am posting a few pics for the experts (99% of the members here are probably more knowledgeable than me) on the forum. I was under the impression that it was worn out and a change was due, unless you guy's think otherwise. From the condition of the plug it looks like there are no issues except the the mixture was a bit lean.

Link to photos

Any input regarding the condition of the old plug would be greatly appreciated.

[Bitter]

those look like normal worn plugs to me, nothing stands out. they don't even look lean for a modern car.