The main reason that you need water heat for a carb/alcohol installation it to prevent fuel drop out (puddling) when the thottle is opened in the relatively long intake runners. With EFI the injectors are typically mounted very close to the intake valves (if it possible aim the injector at the back of the valve). This really reduces the distance for the fuel to puddle out of the air, so water heat may not be needed. What may be possible is to preheat the air to increase vapourization.
