I used to pump Vpower to clean up my engine lastime. Its really good. However the extra mileage doesnt make up for the price difference. It works best with newer engine and with old tech like Wira engine, it didnt make any difference except better power. I used to pump Caltex but sometimes hard to find. Shell still the best.

Instead of the extra power disappear, its more to how little different it was. I think anyone who installed K&N air filter also feel this before. When first installed, sure will feel the extra kick. Once you get used to it, same la.