elboricua

I just washed the wheels on my 2000 e55 today and guess what, the silver just came out in other words they are like a dull polish now i used simple green i didnt think it would damage them i hope i can get them fix or buy new rims, one question are the front rim ssame size as the back? only the tire changes in size right? and what dimensions do i use? plz feedback. I have warranty till 2007 are the rims under warranty?