Xcelplus
I did some research and Xcelplus is a pretty big company. It's the original Slick 50 formula from 1978...The partners of the company had split up and one partner owned the chemical formula, the other owned the "slick 50" name. Slick 50 suddenly was just a bunch of Teflon thrown into a bottle and it doesn't work- that's why Slick 50 got sued by the FTC for false claims. It's bad stuff, and if too much is put in, it will ruin your engine by clogging passage ways etc. That's why they had to change their requirement of how often to use it, and they were sued by people who's engines failed.
Xcelplus is now sold in the USA under it's original 1975 name "Lubrilon". It creates a 1-2 micron layer on top of the metal. It's proven by many different official labs including NASA that it does in fact work, and does create this slippery 1-2 micron layer, and reduces friction about 17%. They have letters directly from the US Department of Energy posted on their website stating that in their own US DOE testing it improved mpg by 7% city and 5.3% highway. In England and Sweden they're test labs concluded an 11% increase in fuel economy. They proved all these tests and this product is the only one on the market that has not been sued by the FTC because it really works.
One last thing I noticed since I'm an aircraft mechanic for the last 15+ years. This product has an FAA approval. You know how hard it is to get any additives approved by the FAA? It's nearly impossible because they don't believe in any of that stuff, they just want you to change the oil and rebuild every ~1800 hours. The aviation tests concluded it reduces engine friction 25%-30% at full power (takeoff). RAM Aircraft engines also swears by this product and recommends it to their customers. (RAM builds higher output top of the line quality replacement engines).
One of the many aviation testimonials was from a customer who lost all his engine oil due to a failed turbocharger seal while flying at 11,500 feet. That normally would have resulted in a crash and probably death of everyone on board. In their case the engine temp never rose, the engine ran normal and they assumed it was just a bad oil pressure gauge. They flew another 1/2 hour!! After landing they found out all the oil was gone. They replaced the turbo, refilled the oil, and did all the required performance tests. The engine was not damaged and was returned to service with no problems.
I'm planning on trying this product, and I don't feel like I'm being scammed either.