Spark Plug Choice for MPG? hotter spark?

[spotaneagle]

I have a table here with gram per ampere-hour rating on types of conductive elements

copper: 2.37
platinum: 1.82

im pretty sure the higher the number on this chart the more conductive an element

I would think copper plugs would provide a hotter spark on some applications an perhaps increase mpg? im not sure about plug mods for mpg.... anyone know?

regardless I read that even thought autozone will sell my platinum plugs for my car, I should be using copper ones, could this be part of the reason? and is the big fuss about platinum overblown?

1) Ford = Motorcraft or Autolite
2) GM = AC Delco
3) Chrysler/Dodge = Champion
4) Toyota = Nippen/Denso (ND)
5) Nissan = NGK
6) Honda = Nippen/Denso (ND) or NGK
7) Most German Vehicles = Bosch

this is what I read
and saturn (copper) ngk's