I believe the GDE tune brings it to like 220 HP 440 TQ at the crank. With that it would move a 6,500 TT well enough but like the others I am not sure of the stability of the narrower wheelbase. Even if you can see around a trailer that long with tow mirrors. Be great for towing a boat. The turbo diesel probably would move the TT as well or better than a naturally aspired 5.3 at altitude at least if its an older 5.3 with an older transmission. Mileage is where it would shine towing. Many average 14 or 15 mpg towing a TT even towing 65.