I use POR-15, but not to cure rust, but to prevent it. I blast all the pieces and etch them before I use the POR-15. If you check out the pics of the chassis in my gallery pics, you will see everything on the chassis is coated with POR-15.

I also use it with fiberglass matt on the interior floorboards. It helps with sound deadening and also adds strength to the overall body/chassis and leaves a nice looking matt finish.

Dean