IMHO, DIY projects are fun and it's great you'd like to do it. But certain projects, like window tinting, should be left to the pros. A soap solution, "slip", need to be used when applying the tint. Your tesla has a lot of electronics and for starters, getting water in the wrong opening, can be disastrous for you. And try to explain that to the service center.
On a more logistic point, trying to tuck the film under the rubber gaskets, aligning the material correctly, not getting dirt particles, cleaning the glass properly to assure tint doesn't bubble or peel, etc. So many variables to consider if you want it to look professional.
But, some people are handier than others, so I don't know what you skills are.
I'm also not sure what film the site is using. They say "ceramic"...but that's a pretty open-ended description as to the "quality" of the film. You'll want to find out what brand and exact film they're using.
For that price, I can assure you, it's not the quality of film you've been reading about on this forum.