This seems really crazy to me but my fully loaded S is in production and I want to switch from 19" to 21" wheels and, despite multiple conversations with California-based Tesla folks, I've been told definitively that I cannot make this change. I'm getting good support from my local Massachusetts-based Tesla team and they're trying to arrange for me to switch my wheels once it lands here, but still can't promise that to me. This MAKES NO SENSE TO ME and is extremely frustrating. I've bought other $100k+ automobiles and, without exception, I'm certain the other manufacturers would have accommodated this change. The wheels go on last, right??? I welcome other experiences/advice any of you may have. Thanks.