Finally I decided to take the car to the shop next week for a complete repaint job. 16 years were not enough to rust the body except some tiny ones under the side moldings, however I am not too happy with the shine and luster anymore, even 5 coats of Klasse doesn't make the paint as shiny as it used to be. What should I consider in order to get another 16 years of rustproof paint? What kind of surface prep and undercoating I should consider? Does the paint brand and type make any difference? The original color is white and I would like to know if a clearcoat application make the finish look better and last longer?

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2001 E200 Kompressor Avantgarde
1987 300E 5-speed
1976 450SLC
1975 280S (sold)
1973 230.6 (sold)