I gave $1100 (leap of faith) to have my last new truck under coated with this AutoArmor stuff that was black and dried -hard-, almost like spray in bedliner, not like rubberized soft undercoating at all. They warranted the truck against surface rust for 100k and against "perforation" for ten years. I know surface rust and perforation of the body do not apply to this thread, but, I'll say that I had that truck (in NY) for 113k for over 6 years and when I just traded it in, it had Zero rust on the frame. There were a few spots on the bottom of the box and along the seems on the bottom of the cab where it was starting to flake/peel off though. My truck sold off the front line of the dealers used truck lineup, in 6 days, for 21k. It was priced the same as two similar ones that he had, that were newer, but not as clean. Without hesitation I would give $1100 to do it again, but the local shop that use to apply that product for the dealer closed up and the new shops here Krown/Ziebart, Im hearing mixed reviews on at best. I have another truck, 4 years old, that I have been hitting with fluid film twice a year. It's taken me about $45 to do it (total) and it is rust free as well, but, only 45k on it. I just bought a case of the nox-Rust stuff and am going to try the yearly re-application of wax thing on the frame (I just put two cans on it, month old truck, washed and dried it over night in garage) and then I -carefully- applied fluid film to the inner body panels and such.