R/T RT came with nivomat leveling shocks and heavy duty cooling. Transmission in the 5.7L is exactly the same as it's big brother SRT.
Where the hitch attaches to the body/frame, the construction is exactly the same for 300/charger/magnum, exactly the same.
Thanks for finding the Chrysler document on towing limits... I had lost the hard copy of that document.
Lets talk about force loads for a minute. As I said before load leveling bars apply a torsional load to the receiver and body. Looking from the drivers side, the torsional load is counter clockwise, lifting the rear and lowering the front. Braking is going to apply a clockwise torsional load, helping to balance the load out, and is structurally the weakest attachment. The rearmost attachment bolts would see the greatest force and at the greatest risk, which is why the tongue weight becomes important. If there's a straight vertical load and then an additional torsional load that translates to bolt tension load... it could over stress the bolt.
We've wasted pages and pages arguing about whether the system is capable or even designed to handle the capability of the load. Many have made their points perfectly clear.
Getting back to my original question, beyond killing grandma and her grandchildren on their way to church, what types of issues come from pulling loads near max load?
Structural I understand, and will carefully watch for any issues or changes.
Transmission, while I still want to get a monitor hooked up, and appreciate the link back on page one, this transmission has been proven to take literally twice the torque my engine will throw at it.
Engine cooling, even in the hottest of hot days, it's rare for both fans to ever come on. Not concerned there.
Trailer tires - brand new, confirm pressure before towing again
Car tires - XL load rated and brand new.
Braking - installed P3 controller and adjusted per instructions. Set to B2 braking level, which is approximately 12% harder braking than car.
Load leveling equipment, I'm going to back off one link and put a little bit more weight on the tongue. Maybe put a bathroom scale under and see how much force is increased with one less link?
Anti sway - never used one, prior owners explanation how to adjust it made zero sense. Tighten the lower clamp until it feels "this tight". How do I know if "this" is too tight or too loose?
One unusual suggestion came from a friend that suggested opening the rear side window and cranking open the vent on top to reduce a lateral pressure wave from a passing truck.