I have been doing some research on some spark plugs. The E3 caught my eye because they claim an increase in power and mpg. My question is, how does this plug compare to other performence plugs and the standard plugs. IE with spending the money and time.

Don't waste your money on those buy some ngk iridium IX and call it a day
NGK FTW

What kind of gains will I be looking at if I switch for stock to these?