Yes to first question. Same process used for body shells and the like. Cost vs time factor. Does the price include the dip. Will you be doing the prep and paint if you sandblast? Paint and supplies must be added to balance sheet. IMO it's not a major concern regarding the inside if not badly rusted. If you feel so inclined then POR-15 the inside. I have been caught in torrential rainstorms and one frame of mine looks fine after 13,000 miles and over 20 years.(Sandblasted, epoxied and semigloss blacked--no extensive treatment to inside of frame was excecuted) Others besides this look just as good. Variables aside, you'll probably be dead before it looks bad enough to re-do for a driver. Scott