Rust prevention

[Eramian 0]

Hi everyone,

I bought an IS300 last year, which do not have rust problems yet because it comes from southern France. But where I live it will be more exposed (cold winter, salted roads).
What mods can be done to prevent rust appearance in the sill just in front on rear wheels (filling, draining holes drilling...), apart from wax injection?
For example I removed the rubber in front of the wheel and it was full of mud!

Any other advice for other zones also appreciated! (front wheel arches have a gutter shape so regular cleaning seems to be a must)