A friend of ours is a performance eng. He swears by this
http://www.boschusa.com/AutoParts/Sp...PlatinumPlus4/
He says he got a least 1.5 - 2 more MPG than with stock plug. All manufactures use cheap plugs he say. With a new air intake and these plugs- it is the cheapest and more for your dollar to get better MPG..
Now to find the part number.