My daughters Note is a similar colour to yours. Her colour code is KY0. I recently addressed ( rubbed down, primed, painted and lacquered) a small bit of rust on tail gate just above wiper arm but tucked in tight in gap below rear window ( so quite hard to rub down). Feel comfortable that I've given it a reasonable amount of protection but it may come back in time. Used spray primer, topcoat, and lacquer from Halfords. It was a learning curve and colour mismatch is quite noticeable to me. Its a very small inconspicuous area otherwise I'd never have attempted it. Id feel generous scoring it at 5 out of 10. Only reason I tackled it myself was that the local chap who had done some reasonably priced good work for me on own my car had a look and said there was always the possibility that it might come back, it was a real pain to colour match that colour in a small area so it would need whole tailgate respraying and the window removal and refitted to chase rusty bit away. He made me feel it was a lot of work and effort and money for what I was looking at and not really worth his workshop space and time doing it. Anyway the main thing I learned with KY0 colour matching a localised respray is beyond my ability. Any other scrapes and scratches that occur will be getting touch up pen to protect and camouflage the exposed primer or bare metal and if and when there's enough of them accumulated to justify it Ill send car to the local guy for 4 days and get all tidied up properly. Hats off to the guys that do it for a living.
