Here is what I come up with according to the numbers you provided.
Shipping weight 11880 + Carrying Capacity of 4620 = Approximate loaded weight of 16500. 20% of that should be a pin weight of 3300. If your door sticker states that you have a payload capacity of 2400 less fuel, passengers hitch and gear...you probably only have about 1700 lbs of payload available.
With that 5er you will be double over your payload capacity. Does that mean the 250 won't pull it....NO! Have a look at any road on the average Friday in the summer and you will see lots of 250/2500's pulling way over what they should. The big question is will you feel safe? I've done my share of white knuckle towing over the years. If it is short trips...you may be fine...but if you are thinking of taking some long trips that may be a different story.
I can understand the extra $150/yr on registration, but the $500 seems too high on insurance! I would check around and get some quotes elsewhere. If you could get it down and find the extra reg $ in the budget you might be happier in the long run to get the 350. That way when the time comes to upgrade the 5er, you would have more truck to upgrade.
JM2C
