In response to your question about xfire rust being almost non-existent is mainly due to the fact that many owners who live in the colder climates of the US do not drive their xfires in the winter. They do this as I do to minimize exposure to road salt. I live in New England and put my xfire away immediately after the first snow or icy road conditions. Once the salt has completely washed away I connect the battery and start another driving season.
Cheers