The legalities around the GVW is something that most people forget. As mentioned, it doesn't matter what you do to the springs, unless you get it properly engineered & the VIN plate changed you still can't carry more than what the GVW states.
Remember also that you have maximum loadings for both front & rear axles. The kerb weight usually includes the driver & a full tank of fuel.
I know it's nice to take everything, including the kitchen sink but it's always best to go as light as possible. It also reduces the likelyhood of breaking down.
M

