I think you can't judge whether TSLA is overvalued or not until they are no longer instantly selling out of all their products. People are bullish on TSLA because they have a product that many, many people want, more than they have the capability to supply.

Once they have their peak production capacity and have surplus stock across all markets we will get a better idea of their true value.

The most that the price of TSLA and BTC have in common is that both their values can be represented on a graph.