i just switched back to the factory plugs from the e3 plugs and there is a difference the stock plugs outperform the e3 plugs call me crazy but they do i have noticed a slight increase in my mpg's already so i am all for staying stock toyota

 

OEM for the win!
I personally think the E3's are a gimmick like the tornado and every other product that comes with an "as seen on tv" tag on the packaging.
Typically the factory knows best.