I'm looking for input on my vehicle and trailer towing calculations as I'm narrowing down my vehicle and trailer combination.

I have no need for a full size pick up truck so I am looking at the Chevrolet Colorado 4 door crew cab with 8 speed automatic and full towing package. I'm trading in my late model Subaru Outback so the truck will also be my daily driver. The Colorado has a gvw of 5400 - 6100 lbs.and a towing capacity of about 7000lbs. I am estimating the Cobra weight at around 2300 lbs and the 16 ' aluminum Serpent Express trailer (per their web site) to weigh 1300 lbs.

So, if I estimate another 200 lbs of gear in the trailer, 1600 lb trailer and 2300 Cobra, we're at 4100 lbs. Someone mentioned to me that I probably want to stay within only 80 % of the 7000lbs limit (5600 lbs) to ensure safe drivability. At 4100 lbs, that puts me well under the 5600 lb range. And my trailer and Cobra weigh less than my vehicle.

Did I miss anything?