"*Custom Grooved Engine Cylinder Heads (Maximises Fuel burn & increases power!)"

I have been trying to figure out how this makes the fuel burn more efficient. Can anyone explain how this works. Would this not create a stress point from where the head would start cracking?
Here is the auction link if it helps
http://www.trademe.co.nz/Trade-Me-Motors/Cars/Mitsubishi/auction-296355853.htm
I am very interested to hear others opinion on this.