If I recall correctly:
X465= air cooled/carb/2wd
X475= liquid cooled/carb/2wd
X485= liquid cooled/fuel injection/2wd
X495= liquid cooled/diesel/2wd
Personally, in a machine of this caliber, I would want a liquid cooled engine, and probably fuel injection. But I might even consider the x465 if I lived in a cooler climate.