Use a Ceramic coating - something like CQuartz UK or Wolfgang Über Ceramic Coating if you are doing it yourself, CQuartz Finest or Modesta if you are having a professional do it (there are of course several other options, but these are excellent).
Water will run off the XPel like you would not believe, and the shine a nano coating imparts is phenomenal. They also last longer than any other last step protectant, and will make cleaning much, much easier, as bugs, dirt, etc. will not stick to the surface nearly as easily.