The way I think about it is that most drivers wouldn't want something on their car that makes it look odd or out of the ordinary, so that takes out some ecomods.
If you were to sell an ecomodded product to someone I could see a response of them claiming "It hasn't improved my mpg" because most drivers wouldn't track their mpg. Not only would some say that but they may want their money back because they haven't seen proven results with their own car even though they are probably just driving like an ass and making their own mpg worse.
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