Care to speculate when we might see those updated EPA numbers?
No, it's hard to say. It could be this year, or it could wait until 2022 model year. In any case it will be no secret when the information is released.
In fact, it already has been released...to CARB (you made me check!):
You can see here there is a new version of the LR AWD (not Performance) which has 524.56 miles of UDDS (unadjusted) range rather than 494.54 miles. This is an updated version of the document as of early March. (Actually it's signed December 2020 - of course - these packs have been around for a long time!)
That's 6% more range. The 494.54 value resulted in 353 miles of EPA range (after the scaling factor of ~0.747 reduction and appropriate weighing with highway test results). That 6% is interestingly high, but remember the prior 494.54 value was achieved with only 78.5kWh (don't think in terms of the BMS values here, they are a different scaling in EPA tests - ~79kWh EPA historically has corresponded with ~77.8kWh SMT). So if you go to 83kWh in the EPA test (corresponding to 81-82kWh SMT), that's about 6% more energy. So with no efficiency changes, I'd expect to see 82-83kWh in the EPA discharge results, and perhaps 81-82kWh SMT. (However, they may have also improved efficiency slightly which would mean lower, more "expected" numbers, like 81.5kWh EPA (the Performance has 80.8kWh EPA discharge energy), and 80.5kWh SMT.)
(In general, again, these comparisons of kWh are not easy, since the EPA numbers and the SMT numbers are never the same; EPA numbers almost always substantially larger (because the EPA values are measured with calibrated equipment, and they may not be scaled exactly the same as the BMS values). I am just providing some background which can mostly be ignored for now - the numbers will be what the numbers are - and they will be available when the EPA numbers are released.)
In any case, as mentioned in October, I'd
expect a final EPA rating over 370 miles (getting to that 370 miles is important for Tesla I would guess - something in the 370s sounds a lot better than something in the 360s when coming from something in the 350s).
So based on this document I would expect an update for 2021, and probably very soon - but I'd still wait until it is official, before purchasing. For all we know, they could end up selling two different vehicle versions in the US - both with the same battery - but one with more capacity unlocked. We just don't know how they will do it, until the EPA information is available.