I am looking at getting a new 4. 5 600. My only concern is the milage. I have heard they don't get good milage. I love my 98, and get 20-22 hiway unloaded. I would hate to trade a good truck for a gas hog. I know they are just coming out, so there is not much data, but if anyone has one, I would like to know what your getting. Thanks.