[Wisha Haddan H3]

If their coating significantly insulates the cylinder wall, I'd be very surprised. But I'd be even more surprised if this company actually knew more about combustion temps and rate-shaping than GM (or any other engine manufacturer).

You know, I rode the oil additive bandwagon a while back. (Yeah I know this one's a fuel additive.) Started with Slick-50 and moved "up" to Pro-long and a couple of others. I ended up with rough starts, noises (the bad kind), hesitation and less power from the damage I did to the engines in those cars. If I'd only spent that time and money on scheduled maintenance, they would have lasted longer and been more reliable in the end.

The more I learn, the more I trust the manufacturer. If an engine's inefficient, the problem is the design, and no additive will fix that.