The sunroofs of the Teslas have an IR blocking coating that is extremely efficient at blocking UV and IR. Adding a layer of window film won't result in a noticeable difference. Don't confuse this with the side glass and back glass though. The factory darkened glass does not have that same coating as the roof does.
Funny thing is between the roof without tint and taking short 10 minute walks on my breaks, I have noticed I'm burned a bit from shirt neckline up. Will be interesting to see after tint installed in a few weeks if this goes away. lol . Never had the issue before during walks for the last few years. I do definitely notice head in car when sitting in it( ac on like 69 or 70) and temp is in 80s or higher. I will let ya guys know.