I personally think that if you pull often, you should own a 5.9 diesel. The do well for fuel mileage, and have a 6.7(pile of junk, oil making pig) manual trans 4wd, and it is good for 14 by its self, and 10 pulling 8k on a car trailer. I personally think that the 2006-07 trucks with the 5.9 are the way to go. Yes they cost more to maintain, but they also hold their value very well too, and the 5.9 trucks are known to see 20+ for MPG hand calculated....