I think it helps. I used to live in New Orleans and the guys that worked in a shop owned by a BMW car club member recommended it. They generally don't believe in Snake oils, since they are a dime a dozen in the French Quarter.

It would be most usefull in really hot places (Florida, Texas, Arizona) or on the race track. Not as usefull in Montana this time or year.

As an engineer, I have read up on how it works and cann't disagree with it. There is a website where a PHD in Heat transfer did a write-up about how it works, he uses it in his track-toy. If a remember correctly, This stuff allows the water in the coolant to work more efficiently by making the surfaces of the cooling jacket more wetable (the angle if refraction is less than 90 degrees) thus the coolant can absorb more heat as it passes through the engine.

The site is www.e30m3performance.com. I don't remember where exactly it is in his site.