Won't the trailer alone be very close or slightly over the towing capacity of the car? I will assume that you have an XI since you are from NY.
The difference between the curb weight of the vehicle and the approved gross weight is only 1,102 pounds. Curb weight is the car plus fuel and oil. The EU adds a 75 kg (165 pound) driver to that weight. I assume BMW does as well.
Max weight on the rear axle for the car is 2,646 pounds. Assuming near 50/50 weight distibution you have 1,907 pounds on the rear axle before cargo, passengers or the tongue weight of the trailer. That leaves a buffer of 739 pounds on the rear axle.
I guess my point is that you need to break out your old calculus and physics books. There isn't a lot of wiggle room on trailer weight, tongue weight, or weight distibution.