I dont have a surgetank, but when I do go to Calder Park I run a full tank, so it adds a bit of extra weight but its safe. On the street I dont put the foot down totally if its anywhere near a qtr, but utes a different as the fuelpump sit lower in the tank. Just dont go thrashing it unless you have over half a tank, or when you get more money go buy a surgetank. And also with the engine, maybe the motor is still tight, that's why its not making the power.