No matter what you're operating, everyone wants more power and better performance. What does that mean to you?
For cars and trucks, it means more horsepower and using less fuel. Same thing for boats - smoother operation and better pickup on the water. Small equipment owners want their mowers and trimmers to have smoother operation as well.
If the engine is in sound mechanical condition, then the biggest culprit for any lost power or performance is the presence of engine deposits, either in the combustion chamber, on the cylinder, on the valves or in the fuel injectors.
Beyond a simple combustion modifier for gas or diesel, and despite lavish promises in the marketplace, the best way to get more power and performance is to restore the engine as close as possible to its new condition. Engines in new condition perform at their peak. It is during their use that "alien" substances like carbon deposits build up in critical areas. It is these substances that move the engine away from the peak power and performance it is engineered to have.