I have a ARB fuel tank.
Best mod I have made to my D40 I get over 1000 k to a tank.
After filling up you travel about 350 k before the needle starts to move, your distance to empty reads low as a close guestimation I generally add 40% onto the reading and that's close enough when planning my next fuel stop.
The fuel gauge reads accurate enough that I have no issues.
Also if your car gets run over by an army tank you know your fuel tank will be ok and will go back into the original shape. Not so sure about the rest of the truck.