I dont currently have any rust on my car but I do have some tiny paint chips. I also have a very deep scratch at the very top just above my rear tire well. Will this make it easier for my car to start rusting? I live in a very damp and rainy city but it only snows 2-3 days per year. Am I at any risk? Also Im having a problem with my trunk leaking. After I open the lid after it rains water will pour in from the left side of the lid. I think it was a factory defect?? Has anyone else with a 4th gen experienced this problem?