I would caution many towing boats with Luxury SUVs... while many are quite adept at towing a car trailer at these weights, hauling a boat is a completely different endeavor. For one, most including the Porsche Cayenne will not control many EOH systems properly. I do know the Audi Q7 will handle an Aerovault electric brake system but not a EOH actuator.
Also understand most of these Lux MFGs increased their payload capacities to take advantage of tax laws in an effort to make purchasing such financially beneficial to those of us who can.
Additionally, it has been my experience as a transport hauler to see many people who do have luxury SUVs, completely unwilling to back them down the ramp into the water to give the boat true freedom of the trailer for launching or loading. It is here where have a short wheelbase vehicle without the proper linking of front to rear wheels in the drivetrain, makes for the most entertaining "Boat Ramp Fails" videos on YouTube!! When the leverage of a boat be unloaded/loaded by power, tips the back of the trailer just enough to lift the rear wheels of the SUV enough to loosen proper traction, the front diff is NOT locked to the rear wheels while in Park or in Reverse. This causes the ENTIRE vehicle to slide down the ramp and with most cases, the brakes have water on them and will not help save the day.
My suggestion is that you look for an alternative vehicle for towing. Enterprise rents 3/4 ton trucks for personal use and towing. The cost of such is less than your deductible.
I also recommend you take a look at a Ram 2500 Laramie or Limited. You will find an Extremely quiet, fully capable truck that I know will get you better MPGs and have all the pulling power you could ever want!