In tank heaters : to heat or not to heat

[EnviroImports.com]

looks like some old water injection system, Im allready using a water/metanol injection in my L400 and my welding truck, it definatly makes a difference, I talked him out of the exhaust heating the fuel line idea, right now I have a stainless steel heat exchanger that is heated by the engine coolant Pre heater core so its right from the rad and gets very hot, im not using a heater in the fuel tank, but I am getting hot fuel back to the tank, I have a pretty good water seperator now so im not worried, one thing with the water injection is the milage goes up, but it can really freak some people out if you have it on manual setting vs boost setting and forget its on when in town, stop at a red light and you can fog the area out with steam coming out the exhaust lol, sure does clean out the system though lol