If you go by the fuel mileage the computer on the Z shows. It's based on injector dwell time and pulse width. At a given dwell and pulse width. The injector should flow x amount of fuel. At any time you change a parameter. It will show a different fuel mileage over a given time frame.

I drive with it on - - - for miles, never had an issue, it is my opinion you will never run out of gas in the Z.

Fill a gas can hold it safely in the car and drive around until you're out of fumes, gives you the best idea of how far you can get once you hit the - - - marks:tup:

If you can afford to drive a Z, you can afford to keep enough gas in the tank. ;)