We pull doubles with our V10 and love it. We pull a 28 foot fifth wheel and a 23 foot boat behind the fifth wheel. Towing about 13,500 pounds when loaded. And yes, it's legal in California, Arizona and Utah; the usual places we tow. The rig is at the maximum legal length at 75 feet from bumper to prop. There are some more mods I want to do to it; i.e. Superchips 1715, and change my gears to 4.10's. Have 3.73's now and added 35" tires; now it's like stock with 3.56's. Maybe I should go to 4.33's. Anybody towing similar weight? Any suggestions on gearing?