Road salt, rock salt or any ice melt products will eventually rot away any exposed metal. I have a 2004 Chevy that I expressly bought from a place in Kansas for the same reason. I grew up in Detroit and now live in North Carolina. Dumass me did not check on what they used in Kansas when it snowed. Good old Morton rock salt. In 2011, I not only had to replace the fuel line, but the brake lines that ran to the rear brakes as well. I did it myself so I can't tell you how much anything costs when a mechanic does it but, $200 sounds fair to me.