I have a 1989 Porsche 928 GT, guards red and there are a few areas of concern with the paint. Both upper door sills have water spots and I am unable to remove them. I have heard some people say to use vinegar to remove them. I currently use P21S paintwork cleanser or 3M imperial hand glaze followed by blitz wax or P21S carnauba. Any suggestions on how to remove the spots or is this just a fact of life with a thirteen year old car? Also, any advice on making my paint look glossy/wet. Thanks for any insight you can provide. Car stays garaged and covered when not in use.