Salt under your tires? You mean gravel / sand. I suppose course rock salt would have the same effect, due to it's texture, but the saline in it doesn't matter. You're looking for traction you're not going to melt the ice away lol.
Although the proper setup helps a lot (weight over driving wheels, good tires, etc) 90% of it comes down to driving ability and experience in those conditions. You can definitely get by with a crappy setup if you know how to properly handle it (and I'm not talking about drifting here, I'm talking about proper feathering and and not spinning your tires, or heavy braking, etc)