The GVWR is set in stone by the maker of your vehicle, and no amount of helper springs will change this. However, a helper spring can decrease sag by up to 2 inches or more in a vehicle. By leveling out the vehicle, all the components in your truck are working far less to carry a lot more. This means that your vehicle will function as if it was carrying a lot less than it is. They will help you to tow up to GVWR, but no aftermarket products can increase the GVWR.