Based on what you said, I would go Krown based on cost alone $300 for an additional 6 months doesn't seem right to me, Particularly if Krown comes with a warranty.Also anyone who is getting rustproofing…my options are Krown for $150 needs to be done every year or Corrosion Free which is good for 18 months but comes in at $450 each time. Anyone have experience with either? Read that Corrosion Free is more effective than crown and less messy as well as hitting more places but also read Krown gets into more places since it’s more fluid.