Regarding the imperial vs. US gallons, my figures for the Blazer were imperial (figured out over multiple tanks and multiple years), and the one's for the Tahoe were US (because that's what the onboard computer gives me. Yes, Ford and GM are both looking at a lightweight diesel option (half ton friendly, basically). GM has a V6 Izusu Duramax in the wings (an a engine I really wish was available when I bought the Tahoe), which should prove a good peformer. - dan