Yes, I voted heavy duty because my 19' inboard/outboard boat weighs about 3250# with trailer fully loaded with gear, I know the Ex is capable of towing more, especially with the 5.0L and 4r70w, but I would not want to pull more then this with it, especially in the rocky mountains.
I have a hidden hitch and hard wired trailer plug, it tows the boat very very well, even with 4 people and all the gear we need for a weekend+
I cannot wait until next summer, I plan to haul the boat to Utah and Wyoming and it will be so nice with the new 2wd/4x4 transfer case, no more AWD sucking up the MPG and power
Towing mods thus far:
KKM intake, intake spacer, e cam & RR valvetrain, large B&M trans cooler, TM headers, custom exhaust, 2wd, rancho RSX shocks, warrior shackles (to fight spring sag)
Soon: IFS disconnect front axle, 4.10 gears, trans temp gage, poly sway bar bushings, computer tune