Tried a google search for this. Gave up after the first two or three pages. One or two web sites like this discussing its efficacy. ALL the others were selling it in one way or another. To be an accurate test, you shouldn't even know if the device is installed. You should simply continue to keep detailed logs and someone else, at some unnannounced time should install it without your knowledge. After a suitable time, they should secretly remove it while you continue to maintain your data logs. This will prevent you from "feeling" the difference. It will also prevent you from subconciously driving in a different manner in order to achieve the results you desire. Even under these conditions, the test is not scientific enough.

The more expensive the snake oil, the more likely the user is to pronounce success. Electronic deer whistles work much better then plain old plastic ones. Expensive oil works better then less expensive. Anyone read an oil thread on a motorcycle web page? The high dollar oil always works better. Quiter, smoother shifting etc. To be a real test, the owner should have the oil changed by someone else. The test will take some time. The oil may not be changed at all or the high dollar oil may not be installed. 79 cent walmart oil may be installed. This should continue over a very long time with the owner taking note of objective (mpg's etc) and subjective (feels quiter, shifts smoother Etc) measurements over the term of the test.

OTOH, with the continued decrease in the teaching of critical thinking skills in our schools and a never ending supply of wide eyed believers, there's a lot of money to be had in the sales and maintenance of snake oil products.