It seems like the problem is Telsa had one mental image in mind, but anyone that does any number crunching wasn't going to see it that way. There's one price for the Perf, but tires/rims obviously don't have the same actual wholesale cost, so to the outside number cruncher it looks like folks with 19" wheels were getting the raw end of the stick.
GeorgeB basically nailed the way it could have been communicated and folks would have been estatic:
It's all in the messaging. Imagine how well it would have come across if the Perf's tire choices had had an * next to them saying:
"21 inch tires are normally a $3500 upgrade, but Tesla is currently offering them as a free upgrade on the Performance package to our early customers. Any reservation made before the offer ends will have this option if they choose the Performance package. Reservations made after this offer expires will have the 21" option for the normal $3500".
The end result is the same, but Tesla's good intentions come across. Part of the problem in the "no cost" thing is folks are so cynical on marketing speak. Buy one get one free (means it was over priced), "free" maintenance (yea, it's really in the base price), etc. "no cost option" sounds like marketing speak for "built into the price". Showing it's a limited time offer for early reservation holders makes clear a more noble intent.