The GSR comes from the factory with expensive platinum spark plugs, because platinum is much more durable than copper. Copper, on the other hand, is a better conductor, and can give a better spark. Another thing the copper plugs have going in their favor is the fact that they have an extended gap, which means the tip and conductor stick farther into the combustion chamber, putting the spark closer to the center.

Does this mean more power? Does anyone have any direct experience or data about this for a stock N/A GSR motor? The coppers go for around $2 each, while the platinums can be had for about $12 per. For that difference, I'm thinking about switching the coppers more often and pretend I'm getting more power.

 

any hp you may or may not get from switching plugs is all in your head

 

Keep the platinum plugs unless you feel like changing your spark plugs every 7000 miles. Copper plugs won't add any horsepower.