We tried the process on my friend's black Boxster...I wasn't overly impressed with the results because it still left a crater where the chip was. We went back to the old concours method of filling, wet sanding, then polishing with an orbital.
Have you seen this method? Similar in nature, but diferent manufacturer:
http://www.langka.com/
I've read positive results with their product on other boards.
(I used to be a fairly serious concours guy a few years back).