i bought my 98 2500 gmc ext cab 6.5l TD back in February,,, and i can say that i havent been disappointed yet,,, it gets roughly 27mpg back and fourth to work,, and i use it to tow alot,, this truck has towed some heavy ass loads for me and the 6.5 only begs for more,, i had about 1500lbs in the bed of it from Albany new york to altoona pa (about a 7.5 hour drive) and it still got 25-28mpg doing more than high way speeds.. my father has a 94 350 chevy and there is no comparisons to the trucks,, mine rides better tows better and gets way way better fuel mileage,,,