Check the turbo hoses. When I first got my turbo it had terrrible gas mileage. Looked around under the hood and found the turbo hoses (to and from the intercoller) had some big holes. I replaced them and voila! gas mileage went way up. Another good bet is to do the electric fan conversion, that made a huge differnce. I am a grad student so I can't afford bad gas mileage though grad students don't consume anywhere as much beer as undergrads do so at least I have a little more change in my pocket.