[Billett]

There is something that can break 18 mpgs in these. An ls swap and a double overdrive. Not much short of that though... A turbo can help improve economy, but only if you drive it that way. Your best bet is to tune the carb properly, keep your fluids clean and full, check your tire pressure, grease EVERYTHING, and drive it like your grandmother. And I'm sorry to say, but there is no magical carb tune thing that turns gas into fumes and nets over 100 mpgs. If there was every car manufacturer in the world would be doing it stock.

On a side note my fiance's Honda Civic Hybrid gets over 40 mpg. You could always spend all the money you'd put into an EFI setup into buying a more efficient car...