I am thankful every time I drive that I'm able to run software of my choice in my automobile. Mazda never seemed to get around to adding Android Auto to my 2015, and yet I use it whenever I feel like, and I didn't have to pay a dealer $300 to install software!
Yeah, people flash their ECMs all the time. I don't really see how using 3rd party software to boost power in a Tesla is all that different. Just don't cover any damage caused by the tinkering under warranty. Tesla just seems salty that they're missing out on their "DLC" profits.