why is it not wise to buy one of these in wake of expensive diesel? Can someone compare the difference between using a diesel, petrol and CNG ? E.g. how many kilometers will a liter do in a surf or land cruiser by diesel and by petrol or by a CNG vehicle. Diesel rates, petrol rates and CNG rates. A comparison would be very helpful for me to make a decision of purchasing a surf, land cruiser or a car.