I notice on the '12 civics they have "Eco Assist™ System"
will they put it on the "12 Fit?
is it a device that you can just buy that you can add to your
later model honda?

 

Eco Assist requires the system to pull data from a couple of different parts (throttle, speed, fuel usage... and compare to a chart)... THEN, it has to have a way to show you... meaning if you go along Honda's style, you'd have to replace the instrument panel.

BTW, why do you think you need it? I mean, it's just an indicator to tell you what should already know: whether you are driving economically or not.

don't mash the gas or stomp the brakes, and you're halfway there.