[Tommy]

Unless the contents of the additive are listed AND a reputable party has objectively tested those materials, I'd be reluctant to believe most manufacturers claims. And the placebo effect being as strong as it is, I'm also reluctant to rely much on anecdotal claims by well intended friends and acquaintances. For example, I had a motorcycle engine smooth out while running a tank of gas spiked with Sea Foam through it. But I have no idea whether it was the Sea Foam or the tank of gas that made the difference.