Originally Posted by Cvdiver

The real way to check how much of a difference the pressure coming from the pipe makes in temperature is to measure the temp after you fuel your car. The run it for maybe half a tank, and check the fuel temp again. My bet is that it doesn't change the temp much, maybe a couple of degrees at most.

I would suggest people spend more time driving and improving their skills, than trying to get time out of some gadget. The best method to get more time out of a tank is better throttle control.