A very important question. Tesla has quadrupled the past 4 months, and anyone who has played around with bullish option strategies will feel like Gordon Gekko at this stage. The natural response will be to pile on more risk and even more bullish strategies. However, as AudobonB points out, at some price point TSLA will be correctly priced, and above that it will be over-priced. Anyone with extremely bullish leveraged positions will then be at great risk.
Furthermore,
the general market may hold a lot of risk right now. My doomsday scenario starts with some kind of trigger event that leads to a dramatic "back-to-earth" experience in the stock market. I think this is a matter of "when", not "if" (read the link at the start of the paragraph, and maybe some other posts on Zerohedge). With the markets crashing there is a flight to "safe" investments. Tesla gets at double hit: First of all, it tanks because it is priced just on expectations and not on so-called fundamentals. Second, investors also downgrade the expectations, due to concerns about the effects of the crash on demand for the cars.
We could see $60-80 in a few weeks, even if Elon Musk and his team keep doing the fabulous job they are doing.
I am long TSLA for a sum that is a huge investment for me. But this is to buy and hold, and I can stick with it through a dip to $60/share. It might be wise to check if you can live with that kind of dip...