After waking up from my alcohol-induced slumber of 9 hours, I got up to watch the end of the HorsePower show on PowerblockTV on SPEED. They were talking about how much spark plugs can make a difference.

I found this interesting cause they started with a fully bolted 6.0L and ran a series of tests. One with the "leading competitors" plugs, and one with E3 plugs. End result?

+8 HP
+14 LB.FT
+4% mpgs
-43% less NOx
-20% less CO2

The plugs are about $6.00 at O'Reillys and Vatozone.

Here is a link to the article.