For gas saving I will recommend the convertion to propane. In Europe we have been using that for quate sametime now. The fuel economy is almost the same but propane price is half the price of the gasoline. At least here. I can say that the engine responce is better and the engine has more power. Also the propane does not leave carbon deposits in your engine and engine oil. In two words I am very happy. The convertion is really easy and the kit price is about 600 US$. The propane tank goes on the place where the spare tyre is, so it takes no internal space.