I started my own test last week to see how much I really can get out of a tank if I drive the car gently ( Which is hard work! ). All city driving using Shell Optimax, including driving to the meet yesterday, I've completed 200km's using just under a quarter tank. Meaning by the time I hit empty, If I continue driving the way I have I'll have done some 800km's from the 55 litre tank. Normally I average around 600km's, so what am I doing different? Rather than shifting up at around 3500 rpm as per normal, I'm shifting up at 2500rpm or less sometimes and using 5th gear from 60km/h (unless going up hills). Now my mods have given me a little more torque allowing me to do this without the engine bogging down or labouring, I'm not sure how a standard 1zz will do, but give it a try. I'll keep you posted how I finish up on this tank of fuel.