Rooney,
Fg's are are a rare beast and the older ones were used/abused primarily in the snow belt where they were drenched in mag-chloride and put away wet. I just bought a '91 which has a badly rusted frame and all the fasteners shear off before they loosen. The '05-'07 trucks have a nicer cab, bigger engine, and are only saddled with EGR which doesn't seem to cause many problems and is easy to remove if it comes to that. They also have a pretty clean exhaust stream especially compared to earlier mechanical engines. After '07 you get the DPF and ULS diesel requirement. The exhaust is much cleaner but the DPF adds some complexity and probably a small fuel mileage penalty. The newest 3.0 engine also adds SCR which typically allows better engine tune and better economy than the straight DPF engines. In the case of the Fuso (Daimler) engine there is not much real world reporting yet to know how well this is working out. It is working very well on the larger Daimler engines such as the DD15. I have seen some pretty good deals on '06/'05 FG's not far north of you in IA, and WI lately, low mileage in the $18-$20k range. Of course, if you can find a clean rust free FG of an earlier vintage there's nothing wrong with that other than a little less power and a lower top speed. That's my 2 cents worth.
