x2 on the fluid film. It's taken 3 applications now over 2 years or so but the safari van and work truck are well coated now. I found that after 6 months or so the rust on the floors and frame would flake off leaving a dry rust spot that would need to be re-coated. The doors and rockers I did replace on the work truck are still rust-free. They are coated in and out with the fluid film
There is a local shop that sprayed it last time, they did a really nice job. Fluid Film undercoating is all they do. They used to only carry Fluid Film but they carry some other dtuff now too. They have all the special wands and sprayers to get inside everywhere. Plus they have late and Sunday hours which is nice with my work schedule. Takes about 45 minutes to an hour and it's not overly expensive.