Not a simple question. There are a number of reasons why you should always stay under the max, whether you are towing, hauling, or carrying in the bed.
1. The maximum weight is what the truck has been designed to accommodate safely, or at least within the design parameters of the truck. This includes braking effectiveness, suspension articulation, roll control, traction, etc.
2. The weight, depending on how it is calculated, does not include passenger weight, spare tire, optional equipment, the toolbox under your seat etc.
3. Warranty can be affected by your failure or ignorance of the weight limitations of your vehicle. If you are 1000 pounds overweight and try to get something fixed under warranty, they could easily deny it as you exceeded the manufacturer's recommendations.
4. This is probably the one that people ignore the most. If you get in an accident while being that much overweight, you will most likely be charged criminally, and will likely loose your insurance coverage.
The safest and best thing you can do would be stay within the limits. That being said, if you understand what the costs and concerns are of choosing another option, that's your call.
