[Perfectlap]

yeah if the corrosion/water damage didn't penetrate to the base layer there's no need to repaint EVERYTHING. A real pro with a Makita sander could fix most of the clear coat damage and the body shop would just need to do a once over with clear. But if the base layer was chipped then the whole panel would need to be repainted. Sounds like this is the case in Allen's Boxster. At least they could limit the repainting to only those panels.
I was watching an episode of Motorweek or one of these shows and the mechanic's personal C4S Carrera had a pencil eraser sized chip in the rear quarter. I though they were going to show some method of doing a magic fix....nope. They painted the whole quarter panel again just because the chip was down to the metal.