If you don't use Reddit, the user who posted that is someone who actually knows people at Tesla and drops tidbits here and there, it isn't some random Joe looking for attention (also a moderator).
Also, again, lines up with what the poster here who claimed to have chatted with an engineer in the Carolinas with a tester.
Finally, the air quality thing isn't really a big deal (imo) but that's already confirmed by the website in one picture.
Now do I think we are all going to be getting 500 miles per charge all of the time? Probably not, but based on what we know, it doesn't sound all that unreasonable (for the things Hayseed said). It definitely would be nice.
All of that being said - Im still on the boat it is an 85kWh - 90kWh battery.