Hello Mike. According to Edmunds your 2007 Colorado comes with an engine producing 242 Hp. and 242 ft-lbs of torque with a 4 speed automatic transmission and a tow capacity of 4000 lb. You should be fine with a 13 ft. or 16 ft. trailer. While your truck could pull a 17 ft. you might find it a little under powered. A transmission cooler is recommended if you truck doesn't already have one. I am a big fan of trailer
brakes so I would recommend what ever you buy it be equipped with them. Pick up trucks tend to rust from the back, forward. If your truck has a hitch already make sure it is in good condition and if you have one installed make sure the mounting points are solid. Happy shopping, take care. Raz