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and then the disclaimer:

Tow ratings for vehicles should be described as “general guidelines”. Actual towing limits depend on towing speed, highway grades, elevation, desired acceleration, miles towed per year, tow vehicle loading, frontal area of trailer, sway resistance of trailer, etc.
TrailManor provides uniquely easy towing per pound due to the very low wind drag and the very stable ride resulting from axle placement.
Light duty towing of a well-balanced trailer a few hundred pounds above the rating is much safer than towing a lighter, poorly balanced unit with a tendency to sway. Also, towing an upright trailer with large frontal area at highway speeds can damage a transmission even if the trailer weight is below the tow rating.
Adding options, batteries, gear, fluids can increase loaded weights as much as 1000 pounds above the base weight of a specific trailer. You should add 500- 1000 pounds to the base weights to estimate the actual towed weight.
Based on feedback from our owners, we provide the following model guidance:
MODERATE TOWING CONDITIONS
Mostly low altitudes, only occasional steep grades, part time service, normal highway speeds - Models 2619 through 3023 need at least 3500 pound tow rated vehicles and Models 3124 through 3326 need 4000 pound ratings.
SEVERE TOWING CONDITIONS
High mountain towing, full time service - all models will perform better with at least 4000 pound rated tow vehicles.