For some reason, the local tire/wheel store here (a very respected independent wheel and brake specialist, not a chain) told me they wouldn't replace any wheels at all. I think they are frightened of changing anything from factory spec., because you'd think they would want to make a sale. I would rather have a slightly smaller wheel and slightly higher profile tire...the xfire is not that different from the slk and it came standard with 17s. Doesn't seem to be worth the $$, though.