Cant beat the diesel for towing and economy, went down to Lake of the Ozarks this past weekend for Labor Day, I towed my 2 place jet ski trailer that weighs maybe around 2K lbs (1 ski is 790 dry and the other is 840, trailer probably weighs a couple of hundred pounds plus fuel, oil etc.. in the skis). I averaged 12-12.5 mpg round trip doing 70-80mph the entire trip. Now my friend that came with me has a 32 foot Sunsation Dominator with 2 496HO motors and a 110 gallon fuel tank that was about 1/2 full (guessing around 7000-7500 pounds for the boat and whatever the trailer weighs) and a bunch of gear, he has a 2005 3/4 ton silverado quad cab with the Duramax/Allison combo, he has a banks system on it as well (empty the thing flies
). He got 11.5-12 mpg for the entire trip and the power it has while towing that big boat is just phenominal, towing almost 4 times the weight not to mention wind drag from that huge boat he was right where I was mileage wise not to mention the power on tap from the Diesel.