Agreed. Your truck will easily tow anything the bumper hitch is rated for, so that's your limit at this point. Switch to a real hitch and you're probably looking at around 4,000 lbs.
why not, I towed my Suburban 2 miles to the gas station with a Saturn.
For a 4cyl 5 spd? Tow capacity is more like 1500-2000 pounds.