hi. first off, congrats on your first house! i remember the feeling of buying my first place, and it was pretty d*mn good!
i put the floor in about 4-5 years ago, and it has actually held up very well. at one time or another i have had just about every automotive fluid out there on the floor and no damage was done. on the ohter hand, if something very heavy is dragged accross the floor it will scratch the clear top coat. it's very easy to just re - clear the floor though, and the scrach gets filled in.
your garage, looks just like mine did when i started working on mine....exposed studs and bare concrete. you have gota great starting point there!
you make a good point about the salt run off. here in ca, i dont deal with that, but i would guess that it wouldnt affect the floor, except for maybe comsmetically. epoxy flooring comes in tons of colors, so perhaps a lighter color might be better for you. also, you have the option of not doing the super glossy topcoat. this would bring the cost down to about 300 or so for a 2 car garage, and also perhaps not show the salt as much.
if you have any questions about the floor you'd like to discuss over pm, feel free to email me. i have helped 4 friends install similar floors in their garages, so i feel like i have a decent amount of experience with it.
and again, CONGRATS ON YOUR NEW PLACE!