The synthetic long position isn't complex to manage. When it is set up with prices cancelling each other out, one simply gains exposure to the 100 shares of stock, with 1:1 upside and downside as if you owned the stock, especially when held to expiration.
If the position is set up at $300 for a break even, and the stock price is $310 at expiration you gain $10/share x 100. If the stock is $290, you lose $10/share. The risk is in the interim, if the stock is significantly lower than your set up price, you risk the shares being put to you. This can come into play if set up in a company with significant dividends and the put purchaser can gain by calling away the stock to poach the dividend, which is not a problem in $TSLA.
The synthetic long for '19 strikes allows plenty of time for the shares to increase above $300, and exposing you to a $1:$1 gain along with the share price, giving you exposure to 100 shares. You can also usually set them up so you get paid a small amount to open the position.
Punchline is, it is not very complex at all, and has no major downsides other than the intermediate risk of being put shares during a large drop if you weren't expecting it.
Please let me know if there is another scenario I'm missing that has significant risk, different than owning 100 shares of stock.