There are times when I have to drive my '05 ST in nasty winter weather; hence the change to Blizzaks in early December. So, I am in the slush and the salt a good bit.
After trying a few waxes known for durability, I have settled on Collinite. Collinite 845IW is very easy to use (I wipe it on with a foam applicator, and wipe off with a mf towel), and it lasts well through the "wand washes" the ST suffers during winter.
A couple of coats before winter sets in, and I am good to go. If I get a nice day, I will wash, and apply another coat. When using it, do shake the bottle hard for a minute first.
There are those who like Collinite's 476 even better for durability. Could be, but the 845 seems readily available. And, it looks almost as good as my summer LSP (Opti-Seal).