I am looking to purchase a 2015 Longhorn, 5.7, 4WD, 8 speed, 3.21 rear end. The description on the dealer website shows "Towing w/Harness and Trailer Sway Control" I see that it is rated to tow 7790 lbs. My boat weighs about 6000 lbs on a tandem axle trailer with surge brakes both axles, (SC...