Those guys you talked to are correct....in a way. Stopping distance and capabilities are one of the main things about towing capacity, but there are other considerations. Like tongue weight, suspension capability, gear ratio, transmission issues (cooler or no). Trailer capacity of the truck also does not take into account if the trailer has breaks, or if you have a weight distributing hitch (many trucks that tow large campers have one), or sway control bars. I had a 2006 1500 4x2 chevy with a 4.8L v8 and towed a 27 ft camper....with a weight dist. hitch. The weight was within its limits and it towed it ok......but eventually I would have torn up the truck. I now have an 06 F150 5.4 with the towing package and it does MUCH better....handling, power, and stopping are much easier! Tires on the towing vehicle are also important...i always check with my trusted local tire dealer when cheching out the capacities of tires. You can basically take the load of your trailer, divide it by four, and see if each tire can support that weight. This is usually not an issue while towing boats, but FYI.