I just saw a thread about cracking on the porcelain on someone's Performer and another kettle.
Weber replaced their kettles.
I have the same cracking on the bottom of my Weber fireplace, so I thought I would contact Weber.
I sent them photos etc.
Weber said they would not warrantee mine as fireplaces only have a 2 year warrantee.
I asked why fireplaces are only 2 years when some kettles are 10 years?
Weber said they were sorry that they could not answer why.
Oh well, it was worth a try.