I heard that it is bad to let any Nissan get down to the "red zone" on gas before fill up, in the Cube's case, lower than 3 bars, because the fuel pumps heat up too much when the gas tank is low on gas and can crack (cheap materials). Anyone know anything about this? What is the best time to fill up the tank to keep your Cube's engine running like new and the fuel system clean? Also, what gas do you guys use? I have been using Mobil only, and I have had my Cube for a month now.