Gas additives have gain popularity over the years because of their claims to improve performance, reduce emissions, and save fuel. In general, if you have a healthy vehicle, you should not need any of these to enjoy the performance, emissions, and fuel savings you were meant to.
There is no magical elixir that is designed to make your engine magically become more efficient and powerful. About the only time these additives may work is if you are not using the right octane rating fuel as your vehicle requires and you increase it to what it is supposed to be using an additive.
There is no benefit to using more octane than what is required...and the mystery in Marve Mystery Oil should be left at just that...a mystery. The plain simple truth is these gimmicks simply don't offer what they claim and in some cases they can even be dangerous to you, your car, and the environment.