f4 plt

RJFabCAb you wrote "Here's why I ask. With the 'ole 10-15% of your load on the tongue rule, I would have a tongue weight of at least 700 lbs with a 7000 lb load which already exceeds the Cayenne's tongue weight limit."

I asked the same question to engineers at Porsche and did not receive a straight answer except to requite what is in the manual as you have above. I pull a Trailex enclosed and try and keep my tongue weight around 575-600, I have towed with a tongue weight above the recommended ( before I got my tongue weight scale) and had no issues and I have PASM on my Cayenne.

There is also the school of thought that your total towed weight (trailer and cargo) should only weigh out no greater than 90 % of the vehicles recommended towing capacity and even with that 10-12% of the weight being on the tongue still exceeds the Porsche recommended tongue weight. This is one of the issues where I can't get a straight answer from Porsche.

Cuda4x4

The Porsche cayenne is by far the best vehicle you could ever find as long as you want to tow a limit of 7700lb and the tongue weight should not be much over 600 lbs. Porsche does not recommend any weight distribution system for the trailer, as this changes the dynamics of everything. Porsche (mine) has PASM with active air ride. When you connect a trailer and plug it into the vehicle, the transmission will automatically reprogram the shift point as well as the engine torque curve.
it Always remains level. By far the most comfortable and fun vehicle ever built for towing within these limits. The only thing you need to add is extensions for the door mirrors, but these are readily available. All of this is, of course just IMHO...

NelaK

Speeds are generally lower in Europe, especially when towing. As a result the tongue weight rule is actually different in Europe and is probably why the Cayenne is rated for 7700lbs despite a max tongue weight that doesn't seem to support it. They go slower on the other side of the ocean, they also have vehicle specific hitches rather than the generic class based system. In fact if you go slow enough you can apparently pull 285 metric-tonnes with a Cayenne:
The biggest risks with towing over capacity is:

• Overloading your suspension - probably not a limiting factor with the Cayenne
• Damaging your frame - again probably not a limiting factor with the Cayenne. Its a tough vehicle!
• Tire load ratings. You can push tires well past their rated limit without them immediately bursting on you. The Cayenne is specced to use sportier tires with softer rubber to provide maximum traction. If you put too much weight on them, your ride quality will suffer significantly and you increase your risk of damage from pot holes etc. Next they will wear out faster because its softer rubber under a lot more load than expected. Heavy duty tires are often much harder but the additional weight on them essentially 'softens' them up. They will also not deliver their rated performance. And finally they will heat up and wear even faster and become even more vulnerable to damage and ultimately failure.
• Insufficient braking performance. The Cayenne is equipped with a pretty decent braking system. The Turbo S's especially so - they have 380mm brake rotors on the front, 358mm on the rear. As a comparison, a quick googling suggests the Ford F250/350 have somewhere around 330mm? The Ford F440/550's seem to be around 370mm to 390mm. Considering the Cayenne itself is significantly lighter, the brakes are probably up to the task even significantly over the rated tow limit.
• Trailer sway. This is the big one everyone thinks about. This is where the tongue weight requirement comes from.

Speed is probably the biggest determining factor for where your limits are for all of the above. If you just go slower the limit for all of those things changes significantly. Its why when your trailer starts to sway - the solution is to slow down.

Its also coincidentally why every U-Haul trailer has a sign saying never to exceed 55mph/90kmh (which literally everyone ignores) and I think that's also the max speed for towing in Europe while in North America most drivers seem to think that you're supposed to go faster when pulling a trailer.

Its also why you see all sorts of tiny vehicles that would never be approved to tow anything in North America pulling trailers in Europe.

Cuda4x4

The cayenne is by far the best vehicle ever built for towing within the specified limits which are...maximum weight of whatever you are looking to tow, and, the maximum tongue weight of 616lb.
mine is an 09 gts with PASM, so it's not approved for use with any weight distribution hitch system. This does not apply to a cayenne without the PASM.
Anyway, within those limits, it will outperform any pickup truck, in performance, comfort, automatic reprogramming for the torque curve as well as transmission shift points, and, simply because it's a PORSCHE.