Just to let everyone know - I went to the dealership with my 07 Mazda 6 to get something doneand they noticed that the wheels (not alloy wheels/rims but the stock wheels under the plastic wheel covers) had discolorations on them.

They said there was a bulletin out on this and I could get them replaced under the bumper-to-bumper warranty. I am going back soon to get this done and I was pleased that they told me about this without asking. If you have discolored wheels check it out if you are still under warranty!!