I have an 07 is350 and the same thing started happening a couple months ago. I live in Miami, Fl so im pretty sure that salt didn't cause it. My dealer covered all the costs to repaint/refurbish the rims. I got my car back a couple weeks ago and they look great. It only took like 3 days. I hope they can do they same for you. You shouldn't have to pay half the costs. These rims seem to have that problem no matter where you live....good luck !!!